Method and apparatus for beam failure reporting under multicell configuration in a wireless communication system

ABSTRACT

A method and apparatus are disclosed from the perspective of a User Equipment (UE). In one embodiment, the method includes the UE being served and/or configured with a first cell and a second cell. The method also includes the UE transmitting a beam failure recovery request via a PRACH (Physical Random Access Channel) in the second cell in response to the UE detecting that all links associated with monitored control resource set(s) in the second cell have failed. Furthermore, the method includes the UE transmitting a first report via a PUCCH (Physical Uplink Control Channel) in the second cell in response to the UE detecting that all links associated with monitored control resource set(s) in the first cell have failed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is continuation of U.S. patent application Ser. No. 16/251,843, filed Jan. 18, 2019, which claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 62/619,320, filed Jan. 19, 2018, with the entire disclosure of each of the referenced applications incorporated fully herein by reference.

FIELD

This disclosure generally relates to wireless communication networks, and more particularly, to a method and apparatus for beam failure reporting under multicell configuration in a wireless communication system.

BACKGROUND

With the rapid rise in demand for communication of large amounts of data to and from mobile communication devices, traditional mobile voice communication networks are evolving into networks that communicate with Internet Protocol (IP) data packets. Such IP data packet communication can provide users of mobile communication devices with voice over IP, multimedia, multicast and on-demand communication services.

An exemplary network structure is an Evolved Universal Terrestrial Radio Access Network (E-UTRAN). The E-UTRAN system can provide high data throughput in order to realize the above-noted voice over IP and multimedia services. A new radio technology for the next generation (e.g., 5G) is currently being discussed by the 3GPP standards organization. Accordingly, changes to the current body of 3GPP standard are currently being submitted and considered to evolve and finalize the 3GPP standard.

SUMMARY

A method and apparatus are disclosed from the perspective of an User Equipment (UE). In one embodiment, the method includes the UE being served and/or configured with a first cell and a second cell. The method also includes the UE transmitting a beam failure recovery request via a PRACH (Physical Random Access Channel) in the second cell in response to the UE detecting that all links associated with monitored control resource set(s) in the second cell have failed. Furthermore, the method includes the UE transmitting a first report via a PUCCH (Physical Uplink Control Channel) in the second cell in response to the UE detecting that all links associated with monitored control resource set(s) in the first cell have failed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a wireless communication system according to one exemplary embodiment.

FIG. 2 is a block diagram of a transmitter system (also known as access network) and a receiver system (also known as user equipment or UE) according to one exemplary embodiment.

FIG. 3 is a functional block diagram of a communication system according to one exemplary embodiment.

FIG. 4 is a functional block diagram of the program code of FIG. 3 according to one exemplary embodiment.

FIGS. 5A-5C provide exemplary illustrations of three types of beamforming.

FIG. 6 is a reproduction of FIG. 1 of 3GPP R2-162709.

FIGS. 7 and 8 are reproduction of figures of 3GPP R2-160947.

FIG. 9 shows an exemplary deployment with single TRP cell.

FIG. 10 shows an exemplary deployment with multiple TRP cells.

FIG. 11 shows an exemplary 5G cell comprising a 5G node with multiple TRPs.

FIG. 12 shows an exemplary comparison between a LTE cell and a NR cell.

FIG. 13 shows an exemplary combination limitation of beam generation.

FIG. 14 is a reproduction of FIG. 3 of 3GPP R2-162251.

FIG. 15 is a reproduction of FIG. 4 of 3GPP R2-162251.

FIG. 16 a flow chart according to one exemplary embodiment.

FIG. 17 is a flow chart according to one exemplary embodiment.

FIG. 18 is a flow chart according to one exemplary embodiment.

FIG. 19 is a flow chart according to one exemplary embodiment.

FIG. 20 is a flow chart according to one exemplary embodiment.

DETAILED DESCRIPTION

The exemplary wireless communication systems and devices described below employ a wireless communication system, supporting a broadcast service. Wireless communication systems are widely deployed to provide various types of communication such as voice, data, and so on. These systems may be based on code division multiple access (CDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), 3GPP LTE (Long Term Evolution) wireless access, 3GPP LTE-A or LTE-Advanced (Long Term Evolution Advanced), 3GPP2 UMB (Ultra Mobile Broadband), WiMax, 3GPP NR (New Radio), or some other modulation techniques.

In particular, the exemplary wireless communication systems devices described below may be designed to support one or more standards such as the standard offered by a consortium named “3rd Generation Partnership Project” referred to herein as 3GPP, including: R2-162366, “Beam Forming Impacts”, Nokia, Alcatel-Lucent; R2-163716, “Discussion on terminology of beamforming based high frequency NR”, Samsung; R2-162709, “Beam support in NR”, Intel; R2-162762, “Active Mode Mobility in NR: SINR drops in higher frequencies”, Ericsson; R3-160947, TR 38.801 V0.1.0, “Study on New Radio Access Technology; Radio Access Architecture and Interfaces”; R2-164306, “Summary of email discussion [93bis #23][NR] Deployment scenarios”, NTT DOCOMO; 3GPP RAN2 #94 meeting minute; R2-162251, “RAN2 aspects of high frequency New RAT”, Samsung; Final Report of 3GPP TSG RAN WG1 #85 v1.0.0 (Nanjing, China, 23-27 May 2016); Final Report of 3GPP TSG RAN WG1 #86 v1.0.0 (Gothenburg, Sweden, 22-26 Aug. 2016); Final Report of 3GPP TSG RAN WG1 #86bis v1.0.0 (Lisbon, Portugal, 10-14 Oct. 2016); Final Report of 3GPP TSG RAN WG1 #87 v1.0.0 (Reno. USA, 14-18 Nov. 2016); Final Report of 3GPP TSG RAN WG1 #AH1_NR v1.0.0 (Spokane, USA, 16-20 Jan. 2017); Final Report of 3GPP TSG RAN WG1 #88 v1.0.0 (Athens, Greece, 13-17 Feb. 2017); Final Report of 3GPP TSG RAN WG1 #88bis v1.0.0 (Spokane, USA, 3-7 Apr. 2017); Final Report of 3GPP TSG RAN WG1 #89 v1.0.0 (Hangzhou, China, 15-19 May 2017); Final Report of 3GPP TSG RAN WG1 #AH_NR2 v1.0.0 (Qingdao, China, 27-30 Jun. 2017); Final Report of 3GPP TSG RAN WG1 #90 v1.0.0 (Prague, Czech Rep, 21-25 Aug. 2017); Final Report of 3GPP TSG RAN WG1 #AH_NR3 v1.0.0 (Nagoya, Japan, 18-21 Sep. 2017); Final Report of 3GPP TSG RAN WG1 #90bis v1.0.0 (Prague, Czech Rep, 9-13 Oct. 2017); Final Chairman's Note of 3GPP TSG RAN WG1 Meeting #91 (Reno. USA, 27 Nov.-1 Dec. 2017) (updated with email approvals); R1-1710539, “On QCL for different BW parts and other QCL details”, Intel Corporation; R1-1800242, “Remaining issues on DL beam recovery”, CATT; R1-1800734, “Remaining issues on beam management”, InterDigital, Inc.; R2-163879, “RAN2 Impacts in HF-NR”, MediaTeK; R2-162210, “Beam level management<->Cell level mobility”, Samsung; and R2-163471, “Cell concept in NR”, CATT. The standards and documents listed above are hereby expressly incorporated by reference in their entirety.

FIG. 1 shows a multiple access wireless communication system according to one embodiment of the invention. An access network 100 (AN) includes multiple antenna groups, one including 104 and 106, another including 108 and 110, and an additional including 112 and 114. In FIG. 1, only two antennas are shown for each antenna group, however, more or fewer antennas may be utilized for each antenna group. Access terminal 116 (AT) is in communication with antennas 112 and 114, where antennas 112 and 114 transmit information to access terminal 116 over forward link 120 and receive information from access terminal 116 over reverse link 118. Access terminal (AT) 122 is in communication with antennas 106 and 108, where antennas 106 and 108 transmit information to access terminal (AT) 122 over forward link 126 and receive information from access terminal (AT) 122 over reverse link 124. In a FDD system, communication links 118, 120, 124 and 126 may use different frequency for communication. For example, forward link 120 may use a different frequency then that used by reverse link 118.

Each group of antennas and/or the area in which they are designed to communicate is often referred to as a sector of the access network. In the embodiment, antenna groups each are designed to communicate to access terminals in a sector of the areas covered by access network 100.

In communication over forward links 120 and 126, the transmitting antennas of access network 100 may utilize beamforming in order to improve the signal-to-noise ratio of forward links for the different access terminals 116 and 122. Also, an access network using beamforming to transmit to access terminals scattered randomly through its coverage causes less interference to access terminals in neighboring cells than an access network transmitting through a single antenna to all its access terminals.

An access network (AN) may be a fixed station or base station used for communicating with the terminals and may also be referred to as an access point, a Node B, a base station, an enhanced base station, an evolved Node B (eNB), or some other terminology. An access terminal (AT) may also be called user equipment (UE), a wireless communication device, terminal, access terminal or some other terminology.

FIG. 2 is a simplified block diagram of an embodiment of a transmitter system 210 (also known as the access network) and a receiver system 250 (also known as access terminal (AT) or user equipment (UE)) in a MIMO system 200. At the transmitter system 210, traffic data for a number of data streams is provided from a data source 212 to a transmit (TX) data processor 214.

In one embodiment, each data stream is transmitted over a respective transmit antenna. TX data processor 214 formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot data using OFDM techniques. The pilot data is typically a known data pattern that is processed in a known manner and may be used at the receiver system to estimate the channel response. The multiplexed pilot and coded data for each data stream is then modulated (i.e., symbol mapped) based on a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream may be determined by instructions performed by processor 230.

The modulation symbols for all data streams are then provided to a TX MIMO processor 220, which may further process the modulation symbols (e.g., for OFDM). TX MIMO processor 220 then provides N_(T) modulation symbol streams to N transmitters (TMTR) 222 a through 222 t. In certain embodiments, TX MIMO processor 220 applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. N_(T) modulated signals from transmitters 222 a through 222 t are then transmitted from N_(T) antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are received by N_(R) antennas 252 a through 252 r and the received signal from each antenna 252 is provided to a respective receiver (RCVR) 254 a through 254 r. Each receiver 254 conditions (e.g., filters, amplifies, and downconverts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) received symbol streams from N_(R) receivers 254 based on a particular receiver processing technique to provide N “detected” symbol streams. The RX data processor 260 then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by RX data processor 260 is complementary to that performed by TX MIMO processor 220 and TX data processor 214 at transmitter system 210.

A processor 270 periodically determines which pre-coding matrix to use (discussed below). Processor 270 formulates a reverse link message comprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of information regarding the communication link and/or the received data stream. The reverse link message is then processed by a TX data processor 238, which also receives traffic data for a number of data streams from a data source 236, modulated by a modulator 280, conditioned by transmitters 254 a through 254 r, and transmitted back to transmitter system 210.

At transmitter system 210, the modulated signals from receiver system 250 are received by antennas 224, conditioned by receivers 222, demodulated by a demodulator 240, and processed by a RX data processor 242 to extract the reserve link message transmitted by the receiver system 250. Processor 230 then determines which pre-coding matrix to use for determining the beamforming weights then processes the extracted message.

Turning to FIG. 3, this figure shows an alternative simplified functional block diagram of a communication device according to one embodiment of the invention. As shown in FIG. 3, the communication device 300 in a wireless communication system can be utilized for realizing the UEs (or ATs) 116 and 122 in FIG. 1 or the base station (or AN) 100 in FIG. 1, and the wireless communications system is preferably the NR system. The communication device 300 may include an input device 302, an output device 304, a control circuit 306, a central processing unit (CPU) 308, a memory 310, a program code 312, and a transceiver 314. The control circuit 306 executes the program code 312 in the memory 310 through the CPU 308, thereby controlling an operation of the communications device 300. The communications device 300 can receive signals input by a user through the input device 302, such as a keyboard or keypad, and can output images and sounds through the output device 304, such as a monitor or speakers. The transceiver 314 is used to receive and transmit wireless signals, delivering received signals to the control circuit 306, and outputting signals generated by the control circuit 306 wirelessly. The communication device 300 in a wireless communication system can also be utilized for realizing the AN 100 in FIG. 1.

FIG. 4 is a simplified block diagram of the program code 312 shown in FIG. 3 in accordance with one embodiment of the invention. In this embodiment, the program code 312 includes an application layer 400, a Layer 3 portion 402, and a Layer 2 portion 404, and is coupled to a Layer 1 portion 406. The Layer 3 portion 402 generally performs radio resource control. The Layer 2 portion 404 generally performs link control. The Layer 1 portion 406 generally performs physical connections.

3GPP standardization activities on next generation (i.e. 5G) access technology have been launched since March 2015. In general, the next generation access technology aims to support the following three families of usage scenarios for satisfying both the urgent market needs and the more long-term requirements set forth by the ITU-R IMT-2020:

-   -   eMBB (enhanced Mobile Broadband)     -   mMTC (massive Machine Type Communications)     -   URLLC (Ultra-Reliable and Low Latency Communications).

An objective of the 5G study item on new radio access technology is to identify and develop technology components needed for new radio systems which should be able to use any spectrum band ranging at least up to 100 GHz. Supporting carrier frequencies up to 100 GHz brings a number of challenges in the area of radio propagation. As the carrier frequency increases, the path loss also increases.

Based on 3GPP R2-162366, in lower frequency bands (e.g., current LTE bands <6 GHz) the required cell coverage may be provided by forming a wide sector beam for transmitting downlink common channels. However, utilizing wide sector beam on higher frequencies (<<6 GHz) the cell coverage is reduced with same antenna gain. Thus, in order to provide required cell coverage on higher frequency bands, higher antenna gain is needed to compensate the increased path loss. To increase the antenna gain over a wide sector beam, larger antenna arrays (number of antenna elements ranging from tens to hundreds) are used to form high gain beams.

As a consequence the high gain beams being narrow compared to a wide sector beam, multiple beams for transmitting downlink common channels are needed to cover the required cell area. The number of concurrent high gain beams that access point is able to form may be limited by the cost and complexity of the utilized transceiver architecture. In practice, in higher frequencies, the number of concurrent high gain beams is much less than the total number of beams required to cover the cell area. In other words, the access point is able to cover only part of the cell area by using a subset of beams at any given time.

Based on 3GPP R2-163716, beamforming is a signal processing technique used in antenna arrays for directional signal transmission/reception. With beamforming, a beam can be formed by combining elements in a phased array of antennas in such a way that signals at particular angles experience constructive interference while others experience destructive interference. Different beams can be utilized simultaneously using multiple arrays of antennas.

Beamforming can be generally categorized into three types of implementation: digital beamforming, hybrid beamforming, and analog beamforming. For digital beamforming, the beam is generated on the digital domain, i.e. the weighting of each antenna element can be controlled by baseband (e.g. connected to a TXRU (Transceiver Units)). Therefore it is very easy to tune the beam direction of each subband differently across the system bandwidth. Also, to change beam direction from time to time does not require any switching time between OFDM (Orthogonal Frequency Division Multiplexing) symbols. All beams whose directions cover the whole coverage can be generated simultaneously. However, this structure requires (almost) one-to-one mapping between TXRU (transceiver/RF chain) and antenna element and is quite complicated as the number of antenna element increases and system bandwidth increases (also heat problem exists).

For Analog beamforming, the beam is generated on the analog domain, i.e. the weighting of each antenna element can be controlled by an amplitude/phase shifter in the RF (Radio Frequency) circuit. Since the weighing is purely controlled by the circuit, the same beam direction would apply on the whole system bandwidth. Also, if beam direction is to be changed, switching time is required. The number of beams generated simultaneous by an analog beamforming depends on the number of TXRU. Note that for a given size of array, the increase of TXRU may decrease the antenna element of each beam, such that wider beam would be generated. In short, analog beamforming could avoid the complexity and heat problem of digital beamforming, while is more restricted in operation. Hybrid beamforming can be considered as a compromise between analog and digital beamforming, where the beam can come from both analog and digital domain.

FIGS. 5A-5C provide exemplary illustrations of the three types of beamforming.

Based on 3GPP R2-162709 and as shown in FIG. 6, an eNB may have multiple TRPs (either centralized or distributed). Each TRP (Transmission/Reception Point) can form multiple beams. The number of beams and the number of simultaneous beams in the time/frequency domain depend on the number of antenna array elements and the RF (Radio Frequency) at the TRP.

Potential mobility type for NR can be listed as follows:

-   -   Intra-TRP mobility     -   Inter-TRP mobility     -   Inter-NR eNB mobility

Based on 3GPP R2-162762, reliability of a system purely relying on beamforming and operating in higher frequencies might be challenging, since the coverage might be more sensitive to both time and space variations. As a consequence of that the SINR (Signal to Interference Plus Noise Ratio) of that narrow link can drop much quicker than in the case of LTE.

Using antenna arrays at access nodes with the number of elements in the hundreds, fairly regular grid-of-beams coverage patterns with tens or hundreds of candidate beams per node may be created. The coverage area of an individual beam from such array may be small, down to the order of some tens of meters in width. As a consequence, channel quality degradation outside the current serving beam area is quicker than in the case of wide area coverage, as provided by LTE.

Based on 3GPP R3-160947, the scenarios illustrated in FIGS. 7 and 8 should be considered for support by the NR radio network architecture.

Based on 3GPP R2-164306, the following scenarios in terms of cell layout for standalone NR are captured to be studied:

-   -   Macro cell only deployment     -   Heterogeneous deployment     -   Small cell only deployment

Based on 3GPP RAN2 #94 meeting minutes, 1 NR eNB corresponds to 1 or many TRPs. Two levels of network controlled mobility:

-   -   RRC driven at “cell” level.     -   Zero/Minimum RRC involvement (e.g. at MAC/PHY)

FIGS. 9 to 12 show some examples of the concept of a cell in 5G NR. FIG. 9 is a reproduction of a portion of FIG. 1 of 3GPP R2-163879, and shows exemplary different deployment scenarios with single TRP cell. FIG. 10 is a reproduction of a portion of FIG. 1 of 3GPP R2-163879, and shows exemplary different deployment scenarios with multiple TRP cells. FIG. 11 is a reproduction of FIG. 3 of 3GPP R2-162210, and shows an exemplary 5G cell comprising a 5G node with multiple TRPs. FIG. 12 is a reproduction of FIG. 1 of 3GPP R2-163471, and shows an exemplary comparison between a LTE cell and a NR cell.

There are some agreements on beam management in the RAN1 #85 meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #85 v1.0.0 (Nanjing, China, 23-27 May 2016) as follows:

Agreements:

-   -   Following three implementations of beamforming are to be studied         in NR         -   Analog beamforming         -   Digital beamforming         -   Hybrid beamforming         -   Note: The physical layer procedure design for NR can be             agnostic to UE/TRP with respect to the beamforming             implementations employed at TRP/UE, but it may pursue             beamforming implementation specific optimization not to lose             efficiency     -   RAN1 studies both multi-beam based approaches and single-beam         based approaches for these channels/signals/measurement/feedback         -   Initial-access signals (synchronization signals and random             access channels)         -   System-information delivery         -   RRM measurement/feedback         -   L1 control channel         -   Note: The physical layer procedure design for NR can be             unified as much as possible whether multi-beam or             single-beam based approaches are employed at TRP at least             for synchronization signal detection in stand-alone initial             access procedure         -   Note: single beam approach can be a special case of multi             beam approach         -   Note: Individual optimization of single beam approach and             multiple beam approach is possible     -   Multi-beam based approaches         -   In Multi-beam based approaches, multiple beams are used for             covering a DL coverage area and/or UL coverage distance of a             TRP/a UE         -   One example of multi-beam based approaches is beam sweeping:             -   When beam sweeping is applied for a signal (or a                 channel), the signal (the channel) is                 transmitted/received on multiple beams, which are on                 multiple time instances in finite time duration                 -   Single/multiple beam can be transmitted/received in                     a single time instance     -   Single-beam based approaches         -   In single-beam based approaches, the single beam can be used             for covering a DL coverage area and/or UL coverage distance             of a TRP/a UE, similarly as for LTE cell-specific             channels/RS

There are some agreements on beam management in the RAN1 #86 meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #86 v1.0.0 (Gothenburg, Sweden, 22-26 Aug. 2016) as follows:

Agreements:

-   -   The following DL L1/L2 beam management procedures are supported         within one or multiple TRPs:         -   P-1: is used to enable UE measurement on different TRP Tx             beams to support selection of TRP Tx beams/UE Rx beam(s)             -   For beamforming at TRP, it typically includes a                 intra/inter-TRP Tx beam sweep from a set of different                 beams             -   For beamforming at UE, it typically includes a UE Rx                 beam sweep from a set of different beams             -   FFS: TRP Tx beam and UE Rx beam can be determined                 jointly or sequentially         -   P-2: is used to enable UE measurement on different TRP Tx             beams to possibly change inter/intra-TRP Tx beam(s)             -   From a possibly smaller set of beams for beam refinement                 than in P-1             -   Note: P-2 can be a special case of P-1         -   P-3: is used to enable UE measurement on the same TRP Tx             beam to change UE Rx beam in the case UE uses beamforming         -   Strive for the same procedure design for Intra-TRP and             inter-TRP beam management             -   Note: UE may not know whether it is intra-TRP or inter                 TRP beam         -   Note: Procedures P-2&P-3 can be performed jointly and/or             multiple times to achieve e.g. TRP Tx/UE Rx beam change             simultaneously         -   Note: Procedures P-3 may or may not have physical layer             procedure spec. impact         -   Support managing multiple Tx/Rx beam pairs for a UE         -   Note: Assistance information from another carrier can be             studied in beam management procedures         -   Note that above procedure can be applied to any frequency             band         -   Note that above procedure can be used in single/multiple             beam(s) per TRP         -   Note: multi/single beam based initial access and mobility             treated within a separate RAN1 agenda item

R1-168468 Definitions Supporting Beam Related Procedures Nokia, Qualcomm, CATT, Intel, NTT DoCoMo, Mediatek, Ericsson, ASB, Samsung, LGE

{

-   -   Beam management=a set of L1/L2 procedures to acquire and         maintain a set of TRP(s) and/or UE beams that can be used for DL         and UL transmission/reception, which include at least following         aspects:         -   Beam determination=for TRP(s) or UE to select of its own             Tx/Rx beam(s).         -   Beam measurement=for TRP(s) or UE to measure characteristics             of received beamformed signals         -   Beam reporting=for UE to report information a             property/quality of beamformed signal(s) based on beam             measurement         -   Beam sweeping=operation of covering a spatial area, with             beams transmitted and/or received during a time interval in             a predetermined way.             }

There are some agreements on beam management in the RAN1 #86bis meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #86bis v1.0.0 (Lisbon, Portugal, 10-14 Oct. 2016) as follows:

Working assumptions:

-   -   Beam management procedures can utilize at least the following RS         type(s):         -   RS defined for mobility purpose at least in connected mode             -   FFS: RS can be NR-SS or CSI-RS or newly designed RS                 -   Others are not precluded         -   CSI-RS:             -   CSI-RS is UE-specifically configured                 -   Multiple UE may be configured with the same CSI-RS             -   The signal structure for CSI-RS can be specifically                 optimized for the particular procedure             -   Note: CSI-RS can also be used for CSI acquisition     -   Other RS could also be considered for beam management such as         DMRS and synchronization signals         [ . . . ]

Agreements:

-   -   For downlink, NR supports beam management with and without         beam-related indication         -   When beam-related indication is provided, information             pertaining to UE-side beamforming/receiving procedure used             for data reception can be indicated through QCL to UE         -   FFS: Information other than QCL             [ . . . ]     -   For downlink, based on RS (used for beam management) transmitted         by TRP, UE reports information associated with N selected Tx         beams         -   Note: N can be equal to 1             [ . . . ]

Agreements:

-   -   Support at least network triggered aperiodic beam reporting:         -   Aperiodic beam reporting is supported under P-1, P-2, and             P-3 related operations             [ . . . ]

Agreements:

-   -   UL beam management is to be further studied in NR         -   Similar procedures can be defined as DL beam management with             details FFS, e.g.:             -   U-1: is used to enable TRP measurement on different UE                 Tx beams to support selection of UE Tx beams/TRP Rx                 beam(s)                 -   Note: this is not necessarily useful in all cases             -   U-2: is used to enable TRP measurement on different TRP                 Rx beams to possibly change/select inter/intra-TRP Rx                 beam(s)             -   U-3: is used to enable TRP measurement on the same TRP                 Rx beam to change UE Tx beam in the case UE uses                 beamforming                 [ . . . ]

Agreements:

-   -   NR supports mechanism(s) in the case of link failure and/or         blockage for NR         -   Whether to use new procedure is FFS     -   Study at least the following aspects:         -   Whether or not an DL or UL signal transmission for this             mechanism is needed             -   E.g., RACH preamble sequence, DL/UL reference signal,                 control channel, etc.         -   If needed, resource allocation for this mechanisms             -   E.g., RACH resource corresponding mechanism, etc.

There are some agreements on beam management in the RAN1 #87 meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #87 v1.0.0 (Reno, USA, 14-18 Nov. 2016) as follows:

Agreements:

-   -   NR supports with and without a downlink indication to derive QCL         assumption for assisting UE-side beamforming for downlink         control channel reception         -   FFS: details             -   E.g., QCL assumption details             -   E.g., indication signaling (e.g. DCI, MAC CE, RRC, etc.)             -   E.g., beam-related indication for DL control and data                 channels

There are some agreements on beam management in the RAN1 #AH1_NR meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #AH1_NR v1.0.0 (Spokane, USA, 16-20 Jan. 2017) as follows:

Agreements:

-   -   NR supports that UE can trigger mechanism to recover from beam         failure     -   Network explicitly configures to UE with resources for UL         transmission of signals for recovery purpose         -   Support configurations of resources where the base station             is listening from all or partial directions, e.g., random             access region     -   Support transmission of DL signal for allowing the UE to monitor         the beams for identifying new potential beams         [ . . . ]

Agreements:

-   -   UE measurement based on RS for beam management (at least CSI-RS)         composed of K (=total number of configured beams) beams and         reporting measurement results of N selected beams:         -   N is not necessarily fixed number         -   Note: The above procedure based on RS for mobility purpose             is not precluded.     -   Reporting information at least include         -   Measurement quantities for N beam (s)             -   FFS: Detailed reporting contents, e.g., CSI, RSRP or                 both         -   Information indicating N DL Tx beam(s), if N<K             -   FFS: the details on this information, e.g., CSI-RS                 resource IDs, antenna port index, a combination of                 antenna port index and a time index, sequence index,                 etc.                 [ . . . ]

Working Assumption:

-   -   NR supports at least one NW-controlled mechanism for beam         management for UL transmission(s)         [ . . . ]

Working Assupmtions:

-   -   Support at least one of these two alternatives of beam         reporting:         -   Alt 1: UE reports information about TRP Tx Beam(s) that can             be received using selected UE Rx beam set(s).             -   where a Rx beam set refers to a set of UE Rx beams that                 are used for receiving a DL signal                 -   Note: It is UE implementation issues on how to                     construct the Rx beam set.                 -   One example: each of Rx beam in a UE Rx beam set                     corresponds to a selected Rx beam in each panel.             -   For UEs with more than one UE Rx beam sets, the UE can                 report TRP Tx Beam(s) and an identifier of the                 associated UE Rx beam set per reported TX beam             -   NOTE: Different TRP Tx beams reported for the same Rx                 beam set can be received simultaneously at the UE.             -   NOTE: Different TRP TX beams reported for different UE                 Rx beam set may not be possible to be received                 simultaneously at the UE         -   Alt 2: UE reports information about TRP Tx Beam(s) per UE             antenna group basis             -   where UE antenna group refers to receive UE antenna                 panel or subarray             -   For UEs with more than one UE antenna group, the UE can                 report TRP Tx Beam(s) and an identifier of the                 associated UE antenna group per reported TX beam             -   NOTE: Different TX beams reported for different antenna                 groups can be received simultaneously at the UE.             -   NOTE: Different TX beams reported for the same UE                 antenna group may not be possible to be received                 simultaneously at the UE                 [ . . . ]

Agreements:

-   -   For reception of DL control channel, support indication of         spatial QCL assumption between an DL RS antenna port(s), and DL         RS antenna port(s) for demodulation of DL control channel     -   For reception of DL data channel, support indication of spatial         QCL assumption between DL RS antenna port(s) and DMRS antenna         port(s) of DL data channel         -   Different set of DMRS antenna port(s) for the DL data             channel can be indicated as QCL with different set of RS             antenna port(s)         -   Option 1: Information indicating the RS antenna port(s) is             indicated via DCI             -   FFS: whether the information indicating the RS antenna                 port(s) will be assumed only for the scheduled “PDSCH”                 or until the next indication         -   Option 2: Information indicating the RS antenna port(s) is             indicated via MAC-CE, and will be assumed until the next             indication         -   Option 3: Information indicating the RS antenna port(s) is             indicated via a combination of MAC CE and DCI         -   At least one option is supported         -   Note: Indication may not be needed for some cases:

There are some agreements on beam management in the RAN1 #88 meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #88 v1.0.0 (Athens, Greece, 13-17 Feb. 2017) as follows:

Agreements:

-   -   A UE can be configured with the following high layer parameters         for beam management:         -   N≥1 reporting settings, M≥1 resource settings             -   The links between reporting settings and resource                 settings are configured in the agreed CSI measurement                 setting             -   CSI-RS based P-1& P-2 are supported with resource and                 reporting settings             -   P-3 can be supported with or without reporting setting         -   A reporting setting at least including             -   Information indicating selected beam(s)                 -   L1 measurement reporting                 -   FFS details (e.g., based on RSRP or CSI, etc.)             -   Time-domain behavior: e.g. aperiodic, periodic,                 semi-persistent             -   Frequency-granularity if multiple frequency                 granularities are supported         -   A resource setting at least including             -   Time-domain behavior: e.g. aperiodic, periodic,                 semi-persistent             -   RS type: NZP CSI-RS at least             -   At least one CSI-RS resource set, with each CSI-RS                 resource set having K≥1 CSI-RS resources                 -   Some parameters of K CSI-RS resources can be the                     same, e.g. port number, time-domain behavior,                     density and periodicity if any                     [ . . . ]

Agreements:

-   -   For reception of unicast DL data channel, support indication of         spatial QCL assumption between DL RS antenna port(s) and DMRS         antenna port(s) of DL data channel: Information indicating the         RS antenna port(s) is indicated via DCI (downlink grants)         -   The information indicates the RS antenna port(s) which is             QCL-ed with DMRS antenna port(s)     -   FFS: Indication details     -   E.g. explicit indication of RS port/resource ID, or implicitly         derived         -   Note: related signalling is UE-specific     -   Candidate signalling methods for beam indication for a NR-PDCCH         (i.e. configuration method to monitor NR-PDCCH)         -   MAC CE signalling         -   RRC signalling         -   DCI signalling         -   Spec-transparent and/or implicit method         -   Combination of the above             [ . . . ]             Agreement: For the signal(s) utilized for beam management             (BM) for P1/P2/P3, study further whether it is UE-specific             vs. non-UE-specific             [ . . . ]

Agreements:

-   -   Beam failure event occurs when the quality of beam pair link(s)         of an associated control channel falls low enough (e.g.         comparison with a threshold, time-out of an associated timer).         Mechanism to recover from beam failure is triggered when beam         failure occurs     -   Note: here the beam pair link is used for convenience, and may         or may not be used in specification     -   The following signals can be configured for detecting beam         failure by UE and for identifying new potential beams by UE     -   FFS the signals, e.g., RS for beam management, RS for fine         timing/frequency tracking, SS blocks, DM-RS of PDCCH (including         group common PDCCH and/or UE specific PDCCH), DMRS for PDSCH     -   If beam failure event occurs and there are no new potential         beams to the serving cell, FFS whether or not the UE provides an         indication to 3.     -   NR supports configuring resources for sending request for         recovery purposes in symbols containing RACH and/or FFS         scheduling request or in other indicated symbols         [ . . . ]

Agreements:

-   -   The following mechanisms should be supported in NR:         -   The UL transmission to report beam failure can be located in             the same time instance as PRACH:             -   Resources orthogonal to PRACH resources         -   The UL transmission to report beam failure can be located at             a time instance (configurable for a UE) different from PRACH             -   Consider the impact of RACH periodicity in configuring                 the UL signal to report beam failure located in slots                 outside PRACH         -   Additional mechanisms using other channels/signals are not             precluded (e.g., SR, UL grant free PUSCH, UL control)

There are some agreements on beam management in the RAN1 #88bis meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #88bis v1.0.0 (Spokane, USA, 3-7 Apr. 2017) as follows:

Agreements:

-   -   UE Beam failure recovery mechanism includes the following         aspects         -   Beam failure detection         -   New candidate beam identification         -   Beam failure recovery request transmission         -   UE monitors gNB response for beam failure recovery request     -   Beam failure detection         -   UE monitors beam failure detection RS to assess if a beam             failure trigger condition has been met         -   Beam failure detection RS at least includes periodic CSI-RS             for beam management             -   SS-block within the serving cell can be considered, if                 SS-block is also used in beam management as well     -   New candidate beam identification         -   UE monitors beam identification RS to find a new candidate             beam         -   Beam identification RS includes             -   Periodic CSI-RS for beam management, if it is configured                 by NW             -   Periodic CSI-RS and SS-blocks within the serving cell,                 if SS-block is also used in beam management as well     -   Beam failure recovery request transmission         -   Information carried by beam failure recovery request             includes at least one followings             -   Explicit/implicit information about identifying UE and                 new gNB TX beam information             -   Explicit/implicit information about identifying UE and                 whether or not new candidate beam exists         -   Down-selection between the following options for beam             failure recovery request transmission             -   PRACH             -   PUCCH             -   PRACH-like (e.g., different parameter for preamble                 sequence from PRACH)         -   Beam failure recovery request resource/signal may be             additionally used for scheduling request     -   UE monitors a control channel search space to receive gNB         response for beam failure recovery request         -   FFS: the control channel search space can be same or             different from the current control channel search space             associated with serving BPLs

There are some agreements on beam management in the RAN1 #89 meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #89 v1.0.0 (Hangzhou, China, 15-19 May 2017) as follows:

Agreements:

-   -   Support spatial QCL assumption between antenna port(s) within a         CSI-RS resource(s) and antenna port of an SS Block (or SS block         time index) of a cell         -   The other QCL parameters not precluded         -   FFS: indication either explicit or implicit or configurable             or a default         -   Note: default assumption may be no QCL     -   Configuration of QCL for UE specific NR-PDCCH is by RRC and         MAC-CE signalling         -   Note that MAC-CE is not always needed         -   FFS: necessity of DCI signalling         -   Note: For example, DL RS QCLed with DMRS of PDCCH for delay             spread, Doppler spread, Doppler shift, and average delay             parameters, spatial parameters             Agreement: Cell-specifically configured CSI-RS is not             supported for beam management             [ . . . ])

Agreements:

-   -   NR supports CSI-RS configuration to support Tx and/or Rx beam         sweeping for beam management conveying at least the following         information         -   Information related to CSI-RS resource configuration             -   E.g., CSI-RS RE pattern, number of CSI-RS antenna ports,                 CSI-RS periodicity (if applicable) etc.         -   Information related to number of CSI-RS resources         -   Information related to number of time-domain repetitions (if             any) associated with each CSI-RS resource             -   FFS: details of time-domain repetitions, e.g., signaling                 for time-domain repetitions may not be explicit         -   FFS signaling details, e.g., explicit indication vs implicit             indication         -   Note this does not imply particular option (IFDMA or             subcarrier scaling or DFT based) for sub time unit partition             [ . . . ]

Agreements:

-   -   Support the following channel(s) for beam failure recovery         request transmission:         -   Non-contention based channel based on PRACH, which uses a             resource orthogonal to resources of other PRACH             transmissions, at least for the FDM case         -   Note: this does not prevent PRACH design optimization             attempt for beam failure recovery request transmission from             other agenda item     -   Support using PUCCH for beam failure recovery request         transmission         -   FFS whether PUCCH is with beam sweeping or not         -   Note: this may or may not impact PUCCH design     -   FFS Contention-based PRACH resources as supplement to         contention-free beam failure recovery resources         -   From traditional RACH resource pool         -   4-step RACH procedure is used         -   Note: contention-based PRACH resources is used e.g., if a             new candidate beam does not have resources for             contention-free PRACH-like transmission             [ . . . ]

Agreements:

-   -   To receive gNB response for beam failure recovery request, a UE         monitors NR PDCCH with the assumption that the corresponding         PDCCH DM-RS is spatial QCL'ed with RS of the UE-identified         candidate beam(s)         -   Detection of a gNB's response for beam failure recovery             request during a time window is supported             -   If there is no response detected within the window, the                 UE may perform re-tx of the request         -   If not detected after a certain number of transmission(s),             UE notifies higher layer entities

There are some agreements on beam management in the RAN1 #AH_NR2 meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #AH_NR2 v1.0.0 (Qingdao, China, 27-30 Jun. 2017) as follows:

[ . . . ]

Agreements:

-   -   RAN1 agrees that the certain number of beam failure recovery         request transmissions is NW configurable by using some         parameters         -   Parameters used by the NW could be:             -   Number of transmissions             -   Solely based on timer             -   Combination of above     -   FFS: whether beam failure recovery procedure is influenced by         the RLF event

There are some agreements on beam management in the RAN1 #90 meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #90 v1.0.0 (Prague, Czech Rep, 21-25 Aug. 2017) as follows:

Agreements:

-   -   Support L1-RSRP reporting of measurements on SS block for beam         management procedures     -   The following configurations for L1-RSRP reporting for beam         management are supported         -   SS block only (with mandatory support by UE)         -   CSI-RS only (with mandatory support by UE)         -   SS block+CSI-RS independent L1 RSRP reporting             -   Joint L1-RSRP using QCL-ed SS-block+CSI-RS is optionally                 supported by UE (with optionally support by UE)                 [ . . . ]

Agreements:

-   -   At least for non-grouping based beam reporting, taking the         following parameter values for further consideration         -   For maximal TX beam numbers for a UE to measure for a given             reporting instance: candidate value is, e.g., around K=[64]         -   For maximal TX beam numbers reported by a UE per reporting             instance are, e.g., N=[1, 2, 4, 8]         -   For L1-RSRP levels, candidate value is, e.g., around [100]             -   Considering maximal L1-RSRP range, e.g., from X dBm to Y                 dBm             -   Considering step-size of L1-RSRP, e.g., Z dB     -   Companies are encouraged to evaluate/analyze appropriate values         considering         -   P1, P2, and P3 procedures         -   The values could be different for aperiodic reporting, and             semi-persistent/periodic reporting if supported         -   The values could be different for PUCCH and PUSCH based             reporting, if supported         -   CSI-RS and/or SS-block related measurement/reporting             [ . . . ]

Agreements:

-   -   Beam failure is declared only when all serving control channels         fail.     -   When a subset of serving control channels fail, this event         should also be handled         [ . . . ]

Agreements:

-   -   In addition to periodic CSI-RS, SS-block within the serving cell         can be used for new candidate beam identification         -   The following options can be configured for new candidate             beam identification             -   CSI-RS only                 -   Note: in this case, SSB will not be configured for                     new candidate beam identification             -   SS block only                 -   Note: in this case, CSI-RS will not be configured                     for new candidate beam identification             -   FFS: CSI-RS+SS block

There are some agreements on beam management in the RAN1 #AH_NR3 meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #AH_NR3 v1.0.0 (Nagoya, Japan, 18-21 Sep. 2017) as follows:

Agreement:

A UE is RRC configured with a list of up to M candidate Transmission Configuration Indication (TCI) states at least for the purposes of QCL indication

-   -   Whether M equal to or larger than 2^(N) is for further study,         where N is the size of the DCI field for PDSCH     -   Each TCI state can be configured with one RS Set     -   Each ID (FFS: details of ID) of DL RS at least for the purpose         of spatial QCL in an RS Set can refer to one of the following DL         RS types:         -   SSB         -   Periodic CSI-RS         -   Aperiodic CSI-RS         -   Semi-persistent CSI-RS             [ . . . ]

Agreement:

-   -   For QCL indication for PDSCH:         -   When TC states are used for QCL indication, the UE receives             an N-bit TCI field in DCI             -   The UE assumes that the PDSCH DMRS is QCL with the DL                 RS(s) in the RS Set corresponding to the signaled TCI                 state                 [ . . . ]

Agreement:

-   -   Support configuration of SSB for a UE to measure and report one         or more L1-RSRP(s)         -   FFS: whether the set of SSBs is all of the SSB beams or a             subset of them         -   Alt1: Support configuration of SSB resources within a             resource setting for beam management.             -   L1-RSRP measurement on these resources is reported         -   Alt2: Support configuration of the RS type (e.g. SSB,             CSI-RS) in a reporting setting for beam management.             -   L1-RSRP measurement on these resources is reported     -   Down-select between the two options         [ . . . ]

Agreement:

WA on trigger condition 1 for beam recovery request transmission is confirmed with following revision

-   -   “Support at least the following triggering condition(s) for beam         failure recovery request transmission:         Condition 1: when beam failure is detected and candidate beam is         identified”

Agreement:

The following working assumption is confirmed

-   -   For beam failure recovery request transmission on PRACH, support         using the resource that is CDM with other PRACH resources         -   Note that CDM means the same sequence design with PRACH             preambles.         -   Note that the preambles for PRACH for beam failure recover             request transmission are chosen from those for             contention-free PRACH operation in Rel-15         -   Note: this feature is not intended to have any impact on             design related to other PRACH resources         -   Further consider whether TDM with other PRACH is needed             Note: Companies may further study the necessity and             feasibility of additional cyclic shifts on the preamble             sequences for transmission of beam failure recovery requests             [ . . . ]

Agreement:

-   -   For new candidate beam identification purpose         -   In CSI-RS only case, a direct association is configured             between only CSI-RS resources and dedicated PRACH resources         -   In SS block only case, a direct association is configured             between only SS block resources and dedicated PRACH             resources         -   In CSI-RS+SS block case (if supported), an association is             configured between resources of CSI-RS/SSB and dedicated             PRACH resources             -   CSI-RS and SSB can be associated with the same dedicated                 resource through QCL association

There are some agreements on beam management in the RAN1 #90bis meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #90bis v1.0.0 (Prague, Czech Rep, 9-13 Oct. 2017) as follows:

Agreement:

Support at least the explicit approach for the update of spatial QCL reference in a TCI state.

-   -   FFS: Additional support for implicit update.     -   Note: In the explicit approach, the TCI state is updated using         either RRC or RRC+MAC-CE based approach     -   Note: In the implicit approach, when a set of aperiodic CSI-RS         resources are triggered, the triggering DCI includes a TC state         index which provides spatial QCL reference for the triggered set         of CSI-RS resources. Following the measurement, the spatial QCL         reference in the RS set corresponding to the indicated TCI state         is updated based on the preferred CSI-RS determined by the UE.         Other operations of implicit approaches are not precluded.         [ . . . ]         {     -   Proposal: Beam measurement and reporting         -   Support Alt #1 for SSB: configuration of SSB resources             within a resource setting for beam management. L1-RSRP             measurement on those configured resources is reported.         -   For non-grouping based beam reporting, support the following             reports parameters:             -   Maximal number of configured Tx beams for beam                 measurement: K equals 64             -   Maximal number of configured Tx beams to be reported in                 one instance: N_max=2, 4 where a subset of N (N⇐N_max                 where N=1, 2, 4) beams can be selected by the gNB and                 indicated to the UE (FFS signaling mechanism)             -   Reporting differential L1-RSRP when multiple beams are                 reported in one reporting instance. Reference is the                 largest L1-RSRP in that reporting instance. FFS other                 reference for differential reporting.             -   Bit-width: 7 bit for L1-RSRP ranging from −140 dBm to                 −44 dBm with 1 dB stepping size (analogous with LTE) and                 4 bit for differential L1-RSRP                 [ . . . ]     -   Proposal: Update the association of TCI state and DL RS         -   Initialization/Update of the ID of a DL RS(s) in the RS Set             used at least for spatial QCL purposes is done at least via             explicit signalling. Support the following methods for the             explicit signalling:             -   RRC             -   RRC+MAC-CE         -   Implicit Update via “implicit association of the DL RS ID(s)             to a TC state based on measurements by the UE.” is FFS     -   FFS from RAN1NR AH3:         -   Mechanisms to initialize/update the ID of a DL RS(s) in the             RS Set used at least for spatial QCL purposes             -   At least the following two mechanisms are FFS: (1)                 explicit signaling to the UE of the DL RS(s) ID and                 corresponding TCI state (2) implicit association of the                 DL RS ID(s) to a TCI state based on measurements by the                 UE.             -   The mechanisms used for different RS types are FFS     -   Proposal: Presence of TCI in DCI     -   For the case when at least spatial QCL is configured/indicated,         support higher-layer UE-specific configuration of whether or not         TCI field is present in DL-related DCI         -   Not present: No dynamic indication of QCL parameters for             PDSCH is provided in DL-related DCI             -   For PDSCH, UE applies higher-layer signalling of QCL                 parameters/indication for determining QCL parameters                 (details: FFS) except for the case of beam management                 without beam-related indication (ref:Annex) where no                 spatial QCL parameters are higher layer configured         -   Present: Details on next proposal.         -   Proposed candidate solutions should consider             -   Below and above 6 GHz DL beam related operation with and                 without beam indication             -   Downlink beam management with and without beam                 indication (ref Annex)     -   Note: this proposal does not apply to the case of beam         management without beam-related indication (ref:Annex)     -   Proposal: Timing issue of beam indication for PDSCH     -   For the case when at least spatial QCL is configured/indicated,         NR supports the beam indication for PDSCH as follows, if TCI         field is present:         -   The TC field is always present in the associated DCI for             PDSCH scheduling irrespective of same-slot scheduling or             cross-slot scheduling.         -   If the scheduling offset <threshold K: PDSCH uses a             pre-configured/pre-defined/rule-based spatial assumption             (details: FFS)             -   Threshold K can be based on UE capability only if                 multiple candidate values of K are supported.         -   If the scheduling offset >=threshold K: PDSCH uses the beam             (spatial QCL parameter) indicated by the N-bit TCI field in             the assignment DCI.     -   Note: this proposal does not apply to the case of beam         management without beam-related indication (ref: Annex)         }         [ . . . ]

Agreement:

-   -   For L1-RSRP and/or beam resource indicators (e.g. CRI or SSB         index) reporting for beam management, support the following UL         channels:         -   Short/long PUCCH         -   PUSCH     -   Support the following reporting types for beam mgmt. on the         above channels         -   For Periodic, support long PUCCH and short PUCCH         -   Semi-persistent—support all channels         -   Aperiodic—support PUSCH and short PUCCH             [ . . . ]

Agreement:

-   -   gNB response is transmitted via a PDCCH addressed to C-RNTI     -   Dedicated CORESET(s) is applied for monitoring gNB response for         BFRQ. The CORESET is down-selected from the following two         alternatives:         -   Alt 1: the same CORESET (s) as before beam failure         -   Alt 2: dedicatedly configured CORESET for beam failure             recovery.             [ . . . ]

Agreement:

Specification supports the CSI-RS+SS block case for the purpose of new candidate beam identification

-   -   The above case is configured by gNB     -   Note: a dedicated PRACH resource is configured to either an SSB         or a CSI-RS resource     -   Following two scenarios are supported when a UE is configured         with CSI-RS+SSB         -   Scenario 1: PRACHs are associated to SSBs only             -   In this scenario, CSI-RS resources for new beam                 identification can be found from the QCL association to                 SSB(s).         -   Scenario 2: Each of the multiple PRACHs is associated to             either an SSB or a CSI-RS resource             [ . . . ]

Working Assumption:

Beam failure detection is determined based on the following quality measure:

Hypothetical PDCCH BLER

[ . . . ]

Proposal:

-   -   Abeam recovery request can be transmitted if the number of         consecutive detected beam failure instance exceeds a configured         maximum number         -   (Working assumption) If hypothetical PDCCH BLER is above a             threshold, it is counted as beam failure instance             -   Note: Beam failure is determined when all serving beams                 fail         -   The candidate beam can be identified when metric X of             candidate beam is higher than a threshold             -   1 or 2 threshold values are introduced                 -   If 2 thresholds are introduced, one is for SSB and                     the other is for CSI-RS             -   One of the following alternatives will be down-selected                 in RAN1 #91                 -   Alt-1: Fixed value                 -   Alt-2: Configurable value by RRC signaling             -   RAN2 should specify the RRC signaling to configuration                 of the threshold         -   Note: for beam failure detection, the UE should aware the             transmission power offset between CSI-RS and DMRS of PDCCH

Agreement:

-   -   For gNB to uniquely identify UE identity from a beam failure         recovery request transmission         -   A PRACH sequence is configured to UE

Working Assumption:

-   -   At least the following parameters should be configured for         dedicated PRACH resources for beam failure recovery         -   Per UE parameters             -   Preamble sequence related parameters                 -   E.g., root sequence, cyclic shift, and preamble                     index             -   Maximum number of transmissions             -   Maximum number of power rampings             -   Target received power             -   Retransmission Tx power ramping step size             -   Beam failure recovery timer         -   Per dedicated PRACH resource parameters             -   Frequency location information             -   Time location, if it is only a subset of all RACH                 symbols (e.g., PRACH mask)             -   Associated SSB or CSI-RS information         -   Note: as a starting point, use initial access preamble             transmission mechanism and parameters. If any issue is             identified, new mechanism can be introduced.             -   No further RRC signalling for above UE parameters is                 required if reusing the same parameter as initial access

There are some agreements on beam management in the RAN1 #91 meeting, as stated in the Final Report of 3GPP TSG RAN WG1 #91 v1.0.0 (Reno, USA, 27 Nov.-1 Dec. 2017) as follows:

Agreement:

Mechanism to indication of source QCL for a resource:

-   -   P-CSI-RS—through RRC configuration         -   FFS: If the spatial QCL can be configured through a             reference to a configured TCI state     -   SP-CSI-RS—configuring the resource(s) through RRC,         activation/deactivation through MAC-CE;         -   The QCL for SP-CSI-RS is indicated in the same MAC-CE             message that activates the SP-CSI-RS.         -   The QCL is provided through an association with one of the M             candidate TC states     -   AP-CSI-RS—         -   Through DCI (AP-CSI-report-triggering state indication)             -   For each AP-CSI-RS resource associated with each                 triggering state, QCL configuration is provided through                 an association with one of the M candidate TCI states by                 RRC                 -   FFS: Value of M             -   FFS: TCI association on NZP-CSI-RS/ZP-CSI-RS based IMR

Agreement:

PUCCH beam indication is introduced by RRC signalling

-   -   Introduce one RRC parameter: PUCCH-Spatial-relation-info         -   Information associating an SSB ID or, a CRI, or a SRI         -   This is per PUCCH resource configuration

Agreement:

For the number of TC states and mapping to DCI bits, N is 3 bits.

-   -   Note: The number of TCI states supported by a UE depends on its         capability

Agreement:

-   -   The state Is-TCI-Present is configured on a per-CORESET basis     -   For beam management with beam indication, on all CORESETs         configured with Is-TCI-Present=false, the TC state used for         PDCCH is reused for PDSCH reception

Agreement:

-   -   A candidate set of DL RSs are configured using RRC mechanism         -   Each state of M TCI states is RRC configured with a downlink             RS set used as a QCL reference, and MAC-CE is used to select             up to 2{circumflex over ( )}N TCI states out of M for PDSCH             QCL indication             -   The same set of M TCI states are reused for CORESET             -   K TCI states are configured per CORESET             -   When K>1, MAC CE can indicate which one TCI state to use                 for control channel QCL indication             -   When K=1, no additional MAC CE signaling is necessary                 [ . . . ]

Agreement:

-   -   When the scheduling offset is <=k, the PDSCH uses QCL assumption         that is based on a default TCI state (e.g. the first state of         the 2{circumflex over ( )}N states used for PDSCH QCL         indication)

Agreement

-   Differential RSRP is computed with reference to the strongest     reported RSRP Step size: 2 dB

Agreement

-   Computation of L1-RSRP as a linear average of each port's RSRP for     the 2-port CSI-RS for beam mgmt.

Agreement

Between initial RRC configuration and MAC CE activation of TCI states, the UE may assume that both PDCCH and PDSCH DMRS are spatially QCL-ed with the SSB determined during initial access

Agreement

-   -   For the beam management use case, support configuration of up to         =16 CSI-RS resources sets per resource setting, and Ks=1^(˜)64         CSI-RS resources per resource set         -   The total number of CSI-RS resources in all sets cannot be             more than 128     -   Note: One set is selected out of S sets in the CSI trigger         states         [ . . . ]

Agreement:

-   -   When the scheduling offset is <=k, and the PDSCH uses QCL         assumption that is based on a default TCI state         -   The default TCI state corresponds to the TCI state used for             control channel QCL indication for the lowest CORESET ID in             that slot

Agreement:

-   -   Modify the RRC parameter PUCCH-Spatial-relation-info as list.         -   Each entry can be SSB ID or, a CRI, or a SRI         -   One or multiple SpatialRelationInfo IE(s) is included in the             list.     -   Introduce MAC-CE signalling to provide spatial relation         information for a PUCCH resource to one of the entries in         PUCCH-Spatial-relation-info     -   If PUCCH-Spatial-relation-info includes one SpatialRelationinfo         IE, UE applies the configured SpatialRelation info and no MAC-CE         is used.

MAC-CE Impact:

TS38.214 Indication Provides PUCCH resource ID | Bitmap of spatial the spatial of size [8] (Bitmap relation for relation activates one of the [8] PUCCH for a PUCCH entries within the RRC resource parameter PUCCH-Spatial- relation-info)

RRC Modification:

PUCCH- New PUCCH- List of configurations of the UE- 38.331 SpatialRelationInfo SpatialRelationInfo spatial relation between Specific reference RS and PUCCH. Reference RS can be SSB/CSI- RS/SRS. SSB Index, NZP-CSI- RS-ResourceConfigId, or SRS- ResourceConfigId [ . . . ]

Agreement

TABLE 1 Beam-failure-recovery-request-RACH-Resource configuration Value RRC parameter range Note/description RootSequenceIndex-BFR {0, 1, . . . , 137} Short sequence only ZeroCorrelationZoneConfig-BFR {0, 1, . . . , 15} Determine cyclic shift. Value range same as IA session PreambleInitialReceivedTargetPower- FFS Value range same as IA session BFR ra-PreambleIndexConfig-BFR FFS Value range same as IA session PreambleTransMax-BFR FFS Value range same as IA session powerRampingStep-BFR FFS CandidateBeamThreshold One threshold for CSIRS Candidate-Beam-RS-List A list of RS indices. The entry of each list can be a SSB index or a CSI-RS resource index PRACH-resource-dedicated-BFR The following fields are defined for each candidate beam RS Candidate-Beam-RS {SSB index RS index that is associated with the or CSI-RS following PRACH resource ID} Note: if the candidate-beam-RS-List includes both CSIRS resource indexes and SSB indexes, AND only SSB indexes are associated with PRACH resources, NR standard should specify a rule that the UE should Monitor both CSI-RS and SSB for New Beam Identification. ra-PreambleIndex-BFR FFS Preamble index used to select one from a sequence pool prach-FreqOffset-BFR FFS FDM'ed to other PRACH resources. Value range same as IA session masks for RACH FFS Time domain mask. resources and/or SSBs Value range same as IA session

TABLE 2 Other RRC parameters related to beam failure recovery RRC parameter (UE- Value specific parameters) range Note/description ResponseWindowSize-BFR FFS Time duration for monitoring gNB response in Beam-Failure-Recovery- Response-CORESET after BFRQ. Similar to ra-ResponseWindowSize Beam-failure-recovery- FFS Details on UE behaviour related to Timer the timer is FFS NrOfBeamFailureInstance FFS Consecutive number of beam failure instances for declaring beam failure Beam-Failure-Recovery- FFS Response-CORESET [ . . . ]

Agreement:

For a UE, only periodic CSI-RS or SSB which is spatially QCL'ed with PDCCH DMRS is used for beam failure detection

-   -   Support explicit configuration for the periodic CSI-RS for beam         failure detection         -   If this configuration is not made, the default mode is the             following:             -   UE expects at least one of periodic CSI-RS or SSB is                 spatially QCL'ed to PDCCH DMRS

Agreement:

The measurement metric for candidate beam selection is L1-RSRP

-   -   An RRC parameter is introduced to configure the threshold value         for L1-RSRP based on CSI-RS         -   Another threshold can be implicitly derived for L1-RSRP             based on SSB             [ . . . ]

Agreement

The BLER used for beam failure recovery reuses RLM default BLER threshold for RLM out-of-sync declaration

Agreement

The starting point of the observation window of gNB response to beam failure recovery request transmission is 4 slots [ . . . ] For email approval by December 6—MediaTek (Weidong) Update after email approval

Agreements:

If the Candidate-Beam-RS-List includes both CSI-RS resource indexes and SSB indexes, AND only SSB indexes are associated with PRACH resources,

-   -   UE identifies PRACH resources for CSI-RS resource(s) in the         Candidate-Beam-RS-List via spatial QCL indication between SSBs         and CSI-RS resources, if UE-identified new beam(s) is associated         with CSI-RS resource(s)         -   UE sends BFRQ through a PRACH resource associated with the             SSB, which is spatially QCLed with the CSI-RS resource.     -   Note: in case the Candidate-Beam-RS-List includes both CSI-RS         resource indexes and SSB indexes, AND only SSB indexes are         associated with PRACH resources, a UE is not expected to be         configured by Candidate-Beam-RS-List a CSI-RS resource which         does not have a spatial QCL association with any of the SSB in         the same Candidate-Beam-RS-List.         Agreements: If there are multiple beams above the threshold for         new beam identification, it is up to UE implementation to select         a PRACH resource associated to the SSB/CSI-RS resource         satisfying the threshold condition.         Agreements: Upon receiving gNB response for beam failure         recovery request transmission     -   UE shall monitor CORESET-BFR for dedicated PDCCH reception until         one of the following conditions is met:         -   Reconfigured by gNB to another CORESET for receiving             dedicated PDCCH and activated by MAC-CE a TCI state if the             configured CORESET has K>1 configured TCI states             -   FFS: if a default TCI state can be assumed for PDCCH                 after reconfiguration without MAC-CE activation         -   Re-indicated by gNB to another TCI state(s) by MAC-CE of             CORESET(s) before beam failure     -   Until the reconfiguration/activation/re-indication of TC         state(s) for PDCCH, UE shall assume DMRS of PDSCH is spatial         QCL'ed with DL RS of the UE-identified candidate beam in the         beam failure recovery request     -   After the reconfiguration/activation/re-indication of TCI         state(s) for PDCCH, UE is not expected to receive a DCI in         CORESET-BFR.     -   Note: this applies to same carrier case.

3GPP R1-1710539 discusses multi-carrier QCL as follows:

On multi-carrier QCL

Similar to LTE, it is expected that NR should be capable of supporting carrier aggregation feature to facilitate downlink and uplink transmission over channels with different bandwidths. The carrier aggregation framework in NR, should be flexible enough to support aggregation of the component carriers in different bands (inter-band CA) as well as component carriers in the same band (intra-band CA), where intra-band CA would be more common scenario for the carrier frequencies above 6 GHz.

In the scenarios with intra-band CA due to use of the same RF and antenna panels, it may be beneficial to consider QCL assumption between antenna ports transmitted on different CCs. The cross-carrier QCL for the antenna ports can reduce or avoid overhead associated with transmission of the beam management reference signals, synchronization reference signals, RRM measurement reference signals or other reference signals that provides the same or similar measurement results on the component carriers.

In general case NR should support independent beam management procedures on different component carriers. However, in practice for the frequency bands above 6 GHz, due to use of the same RF and antenna panels, the selected analog beamforming is typically common for all aggregated component carriers. In addition, the set of the preferred analog beams should be the same across aggregated carriers within operating band that can be used to optimize beam management procedure. More specifically, the beam management procedure in CA case can be simplified and carried out only by the gNB and UE using only one component carrier. In this approach the set of the acquired beams can then be reused for the other component carriers by establishing the corresponding cross-carrier QCL assumptions for the antenna ports wrt to spatial domain QCL parameters of the channel. In the scenario where QCL on different CC is not established, gNB should not use cross-CC QCL indication and request UE to perform independent BM procedures.

Proposal:

-   -   To support beam management procedure in NR, consider         establishing QCL between antenna ports of the reference signals         transmitted on different component carriers wrt to spatial QCL         parameters of the channel (e.g. mean angle-of-arrival and         angle-of-arrival spread)

Similar optimizations can be introduced for the synchronization signals, where the acquired time and frequency offsets on one component carrier are valid for other component carriers. In this case the synchronization procedure can be simplified and carried out by the gNB and UE using only one component carrier. In this approach the acquired timing and frequency offsets can be reused for the other component carrier(s) by establishing the corresponding cross-carrier QCL assumptions for the antenna ports of the reference signals wrt to time and frequency domain QCL parameters of the channel.

Proposal:

-   -   To support synchronization procedures in NR, consider         establishing QCL between antenna ports of the reference signals         transmitted on different component carriers wrt to time and         frequency QCL parameters of the channel (e.g. average delay,         delay spread Doppler shift and Doppler offset)

Similar optimizations can be introduced for the RRM measurement signals, where the RSRP measured on one component carrier may be also valid for other component carriers. In this case the RRM measurements can be improved by averaging or reusing of the RSRP measurements from different component carriers. For example, If QCL assumption is established wrt to power domain QCL parameter (i.e. average gain), RSRQ reports (as defined in LTE) for each component carrier can be obtained by re-using RSRP across the component carriers, without transmitting the RRM measurement signals.

Proposal:

-   -   To support RRM measurements in NR, consider establishing QCL         between antenna ports of the reference signals transmitted on         different component carriers wrt to power QCL parameters of the         channel (e.g. average gain)

3GPP R1-1800242 proposes that beam failure recovery is self-contained in a single carrier as follows:

2.2 Cross-Carrier Scheduling

The current agreements on beam failure recovery apply at least to the case of same-carrier scheduling. It needs to be discussed whether cross carrier aspects should be considered for BFR procedure, e.g.

-   -   Whether PRACH can be sent on a different UL carrier than the one         associated with the DL carrier,     -   Whether CORESET-BFR can be configured in a different carrier         from existing CORESET,     -   Whether CORSET-BFR supports cross-carrier scheduling.         Our views are summarized below:     -   For PRACH carrying beam failure recovery request, we currently         do not see the need to transmit on a non-associated UL carrier.     -   For CORSET-BFR, in theory it can be configured in another         carrier if control resource on the current carrier is congested.         However given that analog beam management is mostly for >6 GHz         where channel bandwidth is abundant, the need of such         configuration is not clear. Furthermore, as new alternative beam         is measured on the current carrier and not valid for other         carrier on which COREST-BFR is configured (unless cross-carrier         spatial QCL is pre-configured), the need of this operation is         further limited.     -   Likewise, the need of cross-carrier scheduling for CORESET-BFR         is not clear.

Proposal: Beam Failure Recovery is Self-Contained in a Single Carrier.

3GPP R1-1800734 proposes that beam management results in one component carrier may be reused in another component carrier, which may lead to a significant overhead reduction, as follows:

It was agreed that NR supports QCL assumptions across carriers [3]. If two component carriers have similar received power distribution in the spatial domain (e.g., two frequencies are sufficiently close), beam management results (e.g., beam measurement and reporting) in one component carrier may be reused in another component carrier, which may lead to a significant overhead reduction. Since it was already agreed that a UE may be RRC configured with a list of Transmission Configuration Indication (TCI) states for the purposes of QCL indication [5], the configured TCI state table may be further extended to include a spatial QCL relationship among different component carriers. For example, whether RSs in a RS set of a TCI state may have similar beam qualities or not. By including such QCL information, part or all information of one TCL state table maintained for one component carrier may be reused for another component carrier. This will reduce the overhead of using multiple TCI state tables for multiple component carriers, and so relief the scalability issue if a UE is configured with multiple component carriers. Proposal 2: TC State Tables should Include the Information of QCL Assumptions Across Carriers.

One or multiple of following terminologies may be used hereafter:

-   -   BS: A network central unit or a network node in NR which is used         to control one or multiple TRPs which are associated with one or         multiple cells. Communication between BS and TRP(s) is via         fronthaul. BS could also be referred to as central unit (CU),         eNB, gNB, or NodeB.     -   TRP: A transmission and reception point provides network         coverage and directly communicates with UEs. TRP could also be         referred to as distributed unit (DU) or network node.     -   Cell: A cell is composed of one or multiple associated TRPs,         i.e. coverage of the cell is composed of coverage of all         associated TRP(s). One cell is controlled by one BS. Cell could         also be referred to as TRP group (TRPG).     -   Beam sweeping: In order to cover all possible directions for         transmission and/or reception, a number of beams is required.         Since it is not possible to generate all these beams         concurrently, beam sweeping means to generate a subset of these         beams in one time interval and change generated beam(s) in other         time interval(s), i.e. changing beam in time domain. So, all         possible directions can be covered after several time intervals.     -   Beam sweeping number A necessary number of time interval(s) to         sweep beams in all possible directions once for transmission         and/or reception. In other words, a signaling applying beam         sweeping would be transmitted “beam sweeping number” of times         within one time period, e.g. the signaling is transmitted in (at         least partially) different beam(s) in different times of the         time period.     -   Serving beam: A serving beam for a UE is a beam generated by a         network node, e.g. TRP, which is currently used to communicate         with the UE, e.g. for transmission and/or reception.     -   Candidate beam: A candidate beam for a UE is a candidate of a         serving beam. Serving beam may or may not be candidate beam.     -   Qualified beam: A qualified beam is a beam with radio quality,         based on measuring signal on the beam, better than a threshold.     -   The best serving beam: The serving beam with the best quality         (e.g. the highest BRSRP value).     -   The worst serving beam: The serving beam with the worst quality         (e.g. the worst BRSRP value).     -   NR-PDCCH: A channel carries downlink control signal which is         used to control communication between a UE and a network side. A         network transmits NR-PDCCH on configured control resource set         (CORESET) to the UE.     -   UL-control signal: An UL-control signal may be scheduling         request (SR), channel state information (CSI), HARQ-ACK/NACK for         downlink transmission     -   Slot: a scheduling unit in NR. Slot duration is 14 OFDM symbols.     -   Mini-slot: A scheduling unit with duration less than 14 OFDM         symbols.     -   Slot format information (SFI): Information of slot format of         symbols in a slot. A symbol in a slot may belong to following         type: downlink, uplink, unknown or other. The slot format of a         slot could at least convey transmission direction of symbols in         the slot.     -   DL common signal: Data channel carrying common information that         targets for multiple UEs in a cell or all UEs in a cell.         Examples of DL common signal could be system information,         paging, RAR.     -   DL URLLC: A type of DL transmission which requires very high         reliability and very low latency. To fulfill the latency         requirement, an example is to transmit DL URLLC in a mini-slot,         e.g. the data duration could be less than 1 slot such as 1-4         OFDM symbol(s) and there may be one or multiple monitoring         occasions for DL URLLC control in a slot. In this example, a UE         is configured with a CORESET to monitor for DL URLLC control         indicating DL URLLC transmission. The CORESET can be configured         on middle symbol of a slot. The DL URLLC transmission may be         transmitted on the following few symbols of the CORESET.

One or multiple of following assumptions for network side may be used hereafter:

-   -   NR using beamforming could be standalone, i.e. UE can directly         camp on or connect to NR.         -   NR using beamforming and NR not using beamforming could             coexist, e.g. in different cells.     -   TRP would apply beamforming to both data and control signaling         transmissions and receptions, if possible and beneficial.         -   Number of beams generated concurrently by TRP depends on TRP             capability, e.g. maximum number of beams generated             concurrently by different TRPs may be different.         -   Beam sweeping is necessary, e.g. for the control signaling             to be provided in every direction.         -   (For hybrid beamforming) TRP may not support all beam             combinations, e.g. some beams could not be generated             concurrently. FIG. 18 shows an example for combination             limitation of beam generation.     -   Downlink timing of TRPs in the same cell are synchronized.     -   RRC layer of network side is in BS.     -   TRP should support both UEs with UE beamforming and UEs without         UE beamforming, e.g. due to different UE capabilities or UE         releases.

One or multiple of following assumptions for UE side may be used hereafter:

-   -   UE may perform beamforming for reception and/or transmission, if         possible and beneficial.         -   Number of beams generated concurrently by UE depends on UE             capability, e.g. generating more than one beam is possible.         -   Beam(s) generated by UE is wider than beam(s) generated by             TRP, gNB, or eNB.         -   Beam sweeping for transmission and/or reception is generally             not necessary for user data but may be necessary for other             signaling, e.g. to perform measurement.         -   (For hybrid beamforming) UE may not support all beam             combinations, e.g. some beams could not be generated             concurrently. FIG. 13 shows an example of combination             limitation of beam generation.     -   Not every UE supports UE beamforming, e.g. due to UE capability         or UE beamforming is not supported in NR first (few) release(s).     -   One UE is possible to generate multiple UE beams concurrently         and to be served by multiple serving beams from one or multiple         TRPs of the same cell.         -   Same or different (DL or UL) data could be transmitted on             the same radio resource via different beams for diversity or             throughput gain.     -   There are at least two UE (RRC) states: connected state (or         called active state) and non-connected state (or called inactive         state or idle state). Inactive state may be an additional state         or belong to connected state or non-connected state.

Based on 3GPP R2-162251, to use beamforming in both eNB and UE sides, practically, antenna gain by beamforming in eNB is considered about 15 to 30 dBi and the antenna gain of UE is considered about 3 to 20 dBi. FIG. 14 (a reproduction of FIG. 3 of 3GPP R2-162251) illustrates gain compensation by beamforming.

From the SINR perspective, sharp beamforming reduces interference power from neighbor interferers, i.e. neighbor eNBs in downlink case or other UEs connected to neighbor eNBs. In TX beamforming case, only interference from other TXs whose current beam points the same direction to the RX will be the “effective” interference. The “effective” interference means that the interference power is higher than the effective noise power. In RX beamforming case, only interference from other TXs whose beam direction is the same to the UE's current RX beam direction will be the effective interference. FIG. 15 (a reproduction of FIG. 4 of 3GPP R2-162251) illustrates a weakened interference by beamforming.

In 5G/NR, in order to provide a huge traffic rate for variable types of requirement and service in the future, wider and higher frequency bandwidths are used to achieve the goal. However, the higher bands in which the transmission is performed, the more severe the propagation loss would be. Hence, in NR, beamforming technology has been considered and accepted as a method to alleviate the problem and improve the coverage. In NR, there may be one or multiple of beam pair links between UE and network to connect. Due to possible blockage or interference or UE movement/rotation, beam quality of beam pair links is likely to change time-variably. Hence, currently in NR, there are some mechanisms for network to trace beam quality of beam pair links between network and UE. For example, network configures one or more than one downlink RS (Reference Signal) for UE to measure, e.g. CSI-RS (Channel State Information Reference Signal) for beam measurement or L1-RSRP (L1 Reference Signal Received Power) computation. Network can configure one or more than one resource set or setting, wherein UE knows the one or more than one resource set/setting is for beam measurement or L1-RSRP computation. Network also configures report configuration for UE to report measured beam quality or L1-RSRP value.

In order to cover a transmission range, network may configure or transmit more than one downlink RS resources toward different transmission directions via different beams, e.g. beam sweeping. These downlink RS resources may be transmitted in different symbols, wherein these symbols can be continuous. Through swept beams or downlink RSs, network can trace the quality of current (serving) beams to UE and be able to find (possible) beam(s) with higher quality. After UE performs measurement. UE is supposed to transmit or report measured beam quality or L1-RSRP based on report configuration, e.g. transmit beam report based on reporting configuration. However, such mechanism could induce considerable overhead due to transmitting downlink RS on more than one symbol for beam measurement and reporting. Not to mention that in multicell or multicarrier scenario, the signaling overhead could be even significant. For instance, for a UE configured with three serving cells, the UE may require to perform beam measurement and/or beam reporting separately on the three serving cells. The overhead, e.g. RSs for beam measurement and/or resource for beam reporting, may increase proportionally to number of serving cells for a UE.

In fact, for intraband carriers. UE is likely to receive downlink traffic from these carriers or cells using the same RF or transceiver or co-located RF or transceiver. In other words, for carriers or serving cells located in the same frequency band or carriers or serving cells whose frequency bands are close. UE can use the same or similar beam to receive downlink transmission from these carriers or cells. In detail, for intraband carriers or serving cells or carriers serving cells that are close in frequency bands, the antenna ports used to receive these carriers/serving cells can be assumed to be quasi co-located (QCL) with respect to at least spatial RX parameters. Even for serving cells whose are interband carriers, if their transmitting nodes are the same or co-located, the QCL with respect to spatial RX parameters of antenna ports among these serving cells can be assumed. According to the above description, the result of beam management in a serving cell may be applied to another one serving cell. Hence, certain level overhead reduction of signaling overhead may be achieved by reusing result of beam management or RS resource measurement in one serving cell for other serving cells.

A first general concept of this invention is that a UE may not be configured with reference signal resource for beam measurement in a serving cell. The reference signal can be used to measure L1-RSRP value. The reference signal can be CSI-RS for beam management or SS (Synchronization Signal) or PBCH (Physical Broadcast Channel) block or sounding reference signal for beam management.

A second general concept of this invention is that a UE may not be configured with beam reporting configuration in a serving cell. The beam reporting configuration is associated with the reference signal for beam measurement. The UE may report measurement result based on the beam reporting configuration after receiving and/or measuring the reference signal (resource) for beam measurement. The UE may report measurement result in unit of L1-RSRP value. The UE may not report CQI (Channel Quality Indicator) according to the report quantity indicated in beam reporting configuration.

A third general concept of this invention is that a UE is configured with a reference (serving) cell, wherein the QCL assumption of antenna ports to receive downlink transmission in some of the other serving cells can refer to the reference cell. For example, a UE can assume the antenna port for receive downlink transmission in a serving cell is QCLed with a downlink reference signal (resource), wherein the downlink reference signal (resource) is transmitted in the reference cell, e.g. QCL respect to spatial Rx parameter. A UE can refer to the QCL assumption to receive downlink transmission in other serving cell.

The UE may be configured with more than one reference cell. A reference cell and a set of serving cells may be grouped into a group, e.g. cell group, wherein the set of serving cells receive downlink transmission by referring to the QCL assumption of the reference cell. PCell may be a reference cell.

Any combination of the above concepts can be done to form a new method. The above concepts and examples can be performed and captured (but not limited to) in the following embodiments.

Exemplar Embodiment 1: In one embodiment, a UE may not be configured with a resource configuration in a first serving cell. The resource configuration could comprise or indicate at least a resource or a resource indication. The UE could receive the resource to measure and/or compute a quality.

In one embodiment, the quality may be L1-RSRP, BLER (Block Error Rate), or hypothetical BLER. A downlink reference signal could be transmitted on the resource (e.g. reference signal or physical channel). The resource or resource configuration could for L1-RSRP computation or beam measurement. The UE could be configured with one or more than one serving cells.

In one embodiment, the resource or resource configuration may comprise any of the followings: time domain behavior (e.g. periodic, semi-persistent or aperiodic) and/or time domain duration of the resource (e.g. number symbols).

Alternatively, the resource or resource configuration may comprise any of the followings: REs mapping (which may be in frequency domain, time domain, code domain), frequency domain bandwidth of the resource, number of (antenna) ports used to transmit the resource, and/or an ID for identification.

In one embodiment, the downlink reference signal could be CSI-RS and/or SSB (Synchronization Signal Block).

In one embodiment, the UE may be configured with a reporting configuration in the first serving cell. Alternatively, the UE may not be configured with a reporting configuration in the first serving cell. The reporting configuration could comprise information of a report. The report or the report configuration could be associated with reporting measured result in unit of L1-RSRP, or with beam measurement.

In one embodiment, the reporting configuration may be linked to the resource configuration for L1-RSRP computation and/or for beam measurement. In one embodiment, the reporting configuration or the report may be linked to resource indicated in the resource configuration for L1-RSRP computation or beam measurement. More specifically, the reporting configuration or the report may be linked to one kind of downlink reference signal transmitted in resource indicated in the resource configuration for L-RSRP computation or beam measurement.

In one embodiment, the reporting configuration could comprise at least time domain behavior of the report. The report could correspond to a measured quality or measurement result. In particular, the report could correspond to a measured quality or measurement result after receiving and/or measuring the resource indicated in the resource configuration. The reporting configuration could indicate at least the quantity of the report. In one embodiment, the quantity of the report may be related to L1-RSRP, CQI, and/or BLER. The UE may not be configured with a reporting configuration indicating that the quantity of the report is L1-RSRP in the first serving cell.

In one embodiment, the reporting configuration may comprise any of the following:

-   -   time domain behaviour of the report, e.g. periodic,         semi-persistent or aperiodic;     -   an ID for identification;     -   association with a downlink bandwidth part or uplink bandwidth         part;     -   reporting granularity in the frequency domain;     -   periodicity of the report, if the time domain behaviour of the         report is periodic or semi-persistent; and/or     -   the slot offset of the report, if the time domain behavior of         the report is periodic or semi-persistent.

In one embodiment, the slot offset of the report may refer to the distance between each report in unit of slot. The slot offset can be replaced with a time unit offset.

The UE may or may not be configured with a second serving cell. In one embodiment, the UE may be configured with the resource configuration in the second serving cell, and/or with the reporting configuration in the second serving cell. The UE may assume that the QCL assumption for receiving one of any downlink transmission in the first serving cell can be referred to the second serving cell. More specifically, the UE may assume that the antenna port(s) for receiving one of any downlink transmission in the first serving cell is quasi co-located with one of any downlink reference signal transmitted in the second serving cell.

The UE may be indicated an index in the first serving cell, wherein the indication or index can be referred to by the UE to receive one of any downlink transmission in the first serving cell. The index may be an index of a downlink resource transmitted on the second serving cell. In one embodiment, a downlink reference signal could be transmitted on the downlink resource.

In one embodiment, the UE may assume that the antenna port(s) for receiving one of any downlink transmission in the first serving cell is quasi co-located with one of any downlink reference signal received in the second serving cell. The UE may use the same spatial RX parameters to receive one of any downlink transmission as that to receive the downlink resource, wherein the downlink resource is indicated or related to the index.

In one embodiment, the index could be CRI (CSI-RS Resource Indicator). Alternatively, the index could SSB index or SSBRI (SSB resource index).

The second serving cell may be configured with a higher layer parameter for QCL indication. In one embodiment, the higher layer parameter may be associated (i) with one of any downlink reference signal transmitted in a serving cell where the higher layer parameter is configured. (ii) with one of any downlink reference signal transmitted in the second serving cell, or (iii) with a QCL type. The UE may receive one of any downlink transmission based on the higher layer parameter configured in the second serving cell. In one embodiment, the first serving cell may or may not be configured with the higher layer parameter. Alternatively, the higher layer parameter may be TCI or TCI state.

In one embodiment, the QCL type may related to any of the followings:

-   -   Doppler shift;     -   Doppler spread;     -   average delay;     -   delay spread; and/or     -   spatial Rx parameter.

The report for the first serving cell based on the report configuration is a first report. The report for the second serving cell based on the report configuration is a second report. The first report could comprise measured result of a first set of reference signals. The second report could comprise measured result of a second set of reference signals. The first set of reference signals may not be the same as the second set of reference signals. In one embodiment, the first set of reference signals may be a subset of the second set of reference signals.

In one embodiment, the content or first report may be different from the content of the second report. More specifically, the bit length of the first report may be less than or equal to that of the second report.

The UE may transmit a report for the first cell, wherein the report comprises the quality measurement result derived from part of a set of the resources in the second cell. In one embodiment, the set of resource could comprise a set of CSI-RS resources or SS or PBCH blocks. In one embodiment, the quality measurement result may mean RSRP or BLER derived by the UE.

In one embodiment, the report may comprise the quality measurement result related to the link quality in the first cell. The report may also comprise index related to the part of a set of the resources and quality value related to the part of a set of the resources.

In one embodiment, the report may be per cell. Furthermore, the report may be for beam reporting of the first cell. The report may be transmitted in the second cell or the first cell. The first cell could be a secondary cell. The second cell could be primary cell.

In one embodiment, the UE could transmit the report in physical uplink control channel. The UE could be configured with resource configuration of the set of resource in the second cell. The set of resource in the second cell could be for beam measurement. More specifically, the set of resource in the second cell could be for beam measurement of the second cell. Alternatively, the set of resource in the second cell could be for beam measurement of the first cell. The quality measurement of the part of the set of resource in the second cell could refer to beam status of the first cell.

In one embodiment, the first cell and the second cell could be secondary cells. The first cell could be a secondary cell, and the second cell could be a primary cell.

Exemplary Embodiment 2: In another embodiment, the UE may not be configured with resource configuration in a first serving cell. The resource configuration could comprise or indicate at least a resource. An uplink reference signal could be transmitted on the resource. The UE could transmit the uplink reference signal on the resource indicated in the resource configuration. The uplink reference signal could be sounding reference signal.

In one embodiment, the resource configuration could indicate the purpose of transmitting the resource or the uplink reference signal. The purpose of transmitting the resource or the uplink reference signal could be for beam management or for L1-RSRP computation. The UE could be configured with one or more than one serving cells.

In one embodiment, the resource or resource configuration may comprise any of the followings: time domain behavior (e.g. periodic, semi-persistent or aperiodic), or the time domain duration of the resource (e.g. number symbols). The resource or resource configuration may also comprise any of the followings: REs mapping (which may be in frequency domain, time domain, code domain), frequency domain bandwidth of the resource, number of (antenna) ports used to transmit the resource, or an ID for identification.

The UE may or may not be configured with a second serving cell. In one embodiment, the UE could be configured with the resource configuration in the second serving cell. The UE could assume that the antenna port(s) for transmitting one of any uplink transmission in the first serving cell is quasi co-located with one of any uplink reference signal transmitted in the second serving cell. More specifically, the UE could use the same spatial TX parameters to transmit one of any uplink transmission as that to transmit one of any uplink transmission in the first serving cell.

The UE may be indicated an index in the first serving cell, wherein the indication or index can be referred to by the UE to transmit one of any uplink transmission in the first serving cell. The index could be an index of an uplink resource transmitted on the second serving cell. The UE could use the same spatial TX parameters to transmit one of any uplink transmission as that to transmit the uplink resource, wherein the uplink resource is indicated or related to the index. The index could be SRI (SRS Resource Indicator).

The first serving cell may not configured with the higher layer parameter. Alternatively, the first serving cell may be configured with the higher layer parameter.

Exemplar Embodiment 3—For a UE served or configured with a first cell and a second cell, the UE could detect that the quality of monitored control resource set in the first cell is worse than a threshold. The quality of the monitored control resource set in the first cell is derived from a first set of resource. The UE may transmit a first report in the second cell.

In one embodiment, the first report may comprise an index related to the first set of resource and a value related to the quality of the monitored control resource set. The first set of resource may comprise a set of CSI-RS resources, or SS (Synchronization Signal) or PBCH (Physical Broadcast Channel) blocks. The quality of monitored control resource set could mean RSRP (Reference Signal Received Power) or BLER (Block Error Rate) derived by the UE.

More specifically, the quality of all monitored control resource sets in the first cell may be worse than the threshold, and the UE may transmit the first report in the second cell. The first report may comprise an index related to the all monitored control resource sets and a value related to the quality of the all monitored control resource sets.

In one embodiment, the UE may not report failed links in a cell other than the first cell in the first report. Additionally, the UE may not report the quality of monitored control resource set in a cell other than the first cell in the first report.

In one embodiment, the UE may detect that all links associated with monitored control resource set in the first cell are failed. The UE may transmit a first report in the second cell. The first report may comprise at least index related to failed links and quality value related to the failed links. In one embodiment, “link” could refer to a connection between the UE and network, e.g. a beam pair link, a beam connection. “A failed link” or “a link fails” could refer to a situation where the quality of the connection between the UE and network falls below a threshold, such as a RSRP or BLER, derived by the UE and related to the beam connection, is below a threshold. In one embodiment, the UE may keep connecting with network via at least the second cell. The first report may be per cell. The first report may comprise one or more indices related to respective failed links and one or more quality values related to respective failed link.

In one embodiment, the quality value may be set to a predetermined value in the first report. The predetermined value may be the allowed minimum quality value to report, e.g. −140 dBm. The quality value may be in unit of dBm or related to RSRP. In one embodiment, if BLER related to a link is below a threshold, the UE may set the quality value of the link as the predetermined value in the first report even though RSRP related to the link is larger than the predetermined value. The index may be a RS resource index.

In one embodiment, the UE could be configured with a first reporting configuration, and the UE could transmit the first report based on the first reporting configuration. The UE could transmit a second report if at least one link associated with monitored control resource set(s) in the first cell is not failed. This may imply that the UE could not transmit the second report if all links associated with monitored control resource set(s) in the first cell is failed

In one embodiment, the UE could be configured with a second reporting configuration. The UE could transmit the second report based on the second reporting configuration. The second report could be per cell. In one embodiment, the second report may not comprise the index (e.g. RS index) related to a failed link, if any. Furthermore, the second report may not comprise the quality value related to a failed link, if any. In addition, the second report may not comprise the quality value related to a failed link, wherein the quality is set to the predetermined value.

In one embodiment, the UE could report a measured result of a second set of resources in the second report, a quality value related to the measured result of the second set of resources indicated by (resource) index, and/or a quality value related to the measured result of the second set of resources indicated in resource configuration. In one embodiment, the second report could be for reporting measured quality of downlink reference signals. The second set of resource may comprise a set of CSI-RS resources, and/or SS/PBCH blocks. In one embodiment, the second report may be for normal beam reporting. The measured result in the second report may comprise RSRP derived or measured from the second set of resources.

In one embodiment, the first report and the second report may have the same format structure (e.g. bit width/length of the index, bit width/length of the quality value, or number of reported link). The first report and the second report could be transmitted in a same uplink resource. The UE may not transmit a request or a preamble on PRACH resource if all links associated with monitored control resource set(s) in the first cell are failed. The first report may be transmitted via physical uplink control channel. The second report may be transmitted via physical uplink control channel.

In one embodiment, if the number of links associated with monitored control resource set(s) in the first cell are less than the allowed number of reported links in the first report, the UE could report at least a candidate link in the first report. The candidate link could be used to replace one of the failed links in the first cell. The UE could report a (resource) index related to the candidate link in the first report, and/or a quality value related to the candidate link in the first report.

In one embodiment, the first set of resources could be transmitted in the first cell and/or the second cell. In one embodiment, the first set of resources could be transmitted in the second cell, and not in the first cell. In one embodiment, the first set of resources could be transmitted in primary cell. The second set of resources could be transmitted in the first cell and/or the second cell. In one embodiment, the second set of resources could be transmitted in the second cell, and not in the first cell. The second set of resources could transmitted in primary cell.

In one embodiment, the first cell could be a secondary cell. The second cell could be a primary cell. The UE may transmit a request or a preamble on PRACH resource if all links associated with monitored control resource set(s) in the second cell am failed. The uplink resource for reporting could refer to frequency domain resource, time domain resource, code domain resource, or spatial domain resource. In one embodiment, the UE could transmit the uplink resource in the second cell. Furthermore, the UE could monitor or receive PDCCH in the control resource set(s).

In one embodiment, the second cell may be the reference cell of the first cell. The antenna port for receive downlink transmission in the first cell may be QCLed with downlink reference signal (resource) transmitted in the second cell, e.g. QCL respect to spatial Rx parameter. The first cell and the second cell could be secondary cells. Alternatively, the first cell could be secondary cell, and the second cell could be primary cell.

In one embodiment, the index could mean a transmission configuration indication (TCI). Association between TCI state and resource for quality measurement could be configured or indicated by higher layer.

FIG. 16 is a flow chart 1600 according to one exemplary embodiment from the perspective of a UE. In step 1605, the UE is served and/or configured with a first cell and a second cell. In step 1610, the UE transmits a beam failure recovery request via a PRACH in the second cell in response to the UE detecting that all links associated with monitored control resource set(s) in the second cell have failed. In step 1615, the UE transmits a first report via a PUCCH in the second cell in response to the UE detecting that all links associated with monitored control resource set(s) in the first cell have failed.

In one embodiment, the UE may not transmit a request or a preamble on PRACH resource if all links associated with monitored control resource set(s) in the first cell have failed. The method of claim 1, wherein the first cell could be a secondary cell, and the second cell could be a primary cell.

In one embodiment, the UE could report a resource index related to a candidate link in the first report. The resource index could be a reference signal resource index, and the reference signal resource index comprises CSI-RS (Channel State Information Reference Signal) index and/or SSB (Synchronization Signal Block) index. The first report may comprise at least an index related to the failed links and a quality value related to the failed links.

In one embodiment, the UE may keep connecting with network via at least the second cell. The UE may transmit a second report when at least one link associated with monitored control resource set in the first cell has not failed, and the second report is for normal beam reporting for reporting measured quality of downlink reference signals. The UE may not transmit the second report when all links associated with monitored control resource set(s) in the first cell has failed. The first report and a second report may have the same format structure, and the format structure may be a bit width or length of the index, a bit width or length of the quality value, or a number of reported links.

In one embodiment, a link fails when quality of the connection between the UE and network falls below a threshold, and the quality of the connection could be RSRP (Radio Resource Control) or BLER (Block Error Rate) derived by the UE. An antenna port for receiving downlink transmission in the first cell may be QCLed (Quasi Co-Located) with downlink reference signal resources transmitted in the second cell.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a UE wherein the UE is served and/or configured with a first cell and a second cell, the device 300 includes a program code 312 stored in the memory 310. The CPU 308 could execute program code 312 to enable the UE (i) to transmit a beam failure recovery request via a PRACH in the second cell in response to the UE detecting that all links associated with monitored control resource set(s) in the second cell have failed, and (ii) to transmit a first report via a PUCCH in the second cell in response to the UE detecting that all links associated with monitored control resource set(s) in the first cell have failed. Furthermore, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.

FIG. 17 is a flow chart 1700 according to one exemplary embodiment from the perspective of a UE. In step 1705, the UE is served and/or configured with a first cell and a second cell. In step 1710, the UE detects quality of monitored control resource set(s) in the first cell is worse than a threshold, wherein the quality of the monitored control resource set(s) in the first cell is derived from a first set of resource. In step 1715, the UE transmits a first report in the second cell, wherein the first report comprises index related to the first set of resource and value related to the quality of the monitored control resource set(s).

In one embodiment, the first set of resource may comprise a set of CSI-RS resources, or SS or PBCH blocks. The quality of monitored control resource set(s) could mean RSRP or BLER derived by the UE.

In one embodiment, the quality of all monitored control resource set(s) in the first cell could be worse than the threshold; and the UE could transmit the first report in the second cell, wherein the first report comprises index related to the all monitored control resource set(s) and value related to the quality of the all monitored control resource set(s). The UE may not report the quality of monitored control resource set(s) in a cell other than the first cell in the first report.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a UE, wherein the UE is served or configured with a first cell and a second cell, the device 300 includes a program code 312 stored in the memory 310. The CPU 308 could execute program code 312 to enable the UE (i) to detect quality of monitored control resource set(s) in the first cell is worse than a threshold, wherein the quality of the monitored control resource set(s) in the first cell is derived from a first set of resource, and (ii) to transmit a first report in the second cell, wherein the first report comprises index related to the first set of resource and value related to the quality of the monitored control resource set(s). Furthermore, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.

FIG. 18 is a flow chart 1800 according to one exemplary embodiment from the perspective of a UE. In step 1805, the UE is served and/or configured with a first cell and a second cell. In step 1810, the UE detects all links associated with monitored control resource set(s) in the first cell are failed. In step 1815, the UE transmits a first report in the second cell, wherein the first report comprises at least index related to failed links and quality value related to the failed links.

In one embodiment, a link may be a connection between the UE and network (e.g. a beam pair link or a beam connection). A link fails when the quality of the connection between the UE and network falls below a threshold, such as when RSRP or BLER derived by the UE related to a beam connection is below a threshold.

In one embodiment, the UE may transmit the first report in the second cell, wherein the first report comprises at least an index related to the failed links and a quality value related to the failed links. The UE may not report failed links in a cell other than the first cell in the first report.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a UE, wherein the UE is served or configured with a first cell and a second cell, the device 300 includes a program code 312 stored in the memory 310. The CPU 308 could execute program code 312 to enable the UE (i) to detect all links associated with monitored control resource set(s) in the first cell have failed, and (ii) to transmit a first report in the second cell, wherein the first report comprises at least index related to failed links and quality value related to the failed links. Furthermore, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.

In the context of the embodiments illustrated in FIGS. 17 and 18, and discussed above, in one embodiment, the UE may keep connecting with network via at least the second cell. The first report may be per cell. Furthermore, the first report may comprise one or more indices related to the failed links, and one or more quality values related to the failed links. The quality value may be set to a predetermined value in the first report. The predetermined value may be the allowed minimum quality value to report. The quality value may be in units of dBm, and may be related to RSRP. In one embodiment, if the BLER related to a link is below a threshold, the UE may set the quality value of the link as the predetermined value in the first report even though RSRP related to the link is larger than the predetermined value.

In one embodiment, the index may be a RS resource index. The UE could be configured with a first reporting configuration, and the UE could transmit the first report based on the first reporting configuration. The UE could also transmit a second report if at least one link associated with monitored control resource set in the first cell is not failed. In addition, the UE could be configured with a second reporting configuration, and the UE could transmit the second report based on the second reporting configuration.

In one embodiment, the second report could be per cell. The second report may not comprise the index (e.g. RS index) related to a failed link, if any. Furthermore, the second report may not comprise the quality value related to a failed link, if any. In addition, the second report may not comprise the quality value related to a failed link, wherein the quality is set to the predetermined value.

In one embodiment, the UE may report a measured result of a second set of resources in the second report, a quality value related to the measured result of the second set of resources indicated by (resource) index, and/or a quality value related to the measured result of the second set of resources indicated in resource configuration. In one embodiment, the second report may be for reporting measured quality of downlink reference signals, and may comprise a set of CSI-RS resources or SS/PBCH blocks. Alternatively, the second report may be for normal beam reporting.

In one embodiment, the measured result of the second set of resources in the second report may comprise RSRP derived from the second set of resources. The first report and the second report have the same format structure (e.g. bit width/length of the index, bit width/length of the quality value, or number of reported link). The first report and the second report may be transmitted in a same uplink resource.

In one embodiment, the UE may not transmit a request or a preamble on PRACH resource if all links associated with monitored control resource set(s) in the first cell are failed. The first report may be transmitted via physical uplink control channel. The second report may be transmitted via physical uplink control channel.

In one embodiment, if the number of links associated with monitored control resource set(s) in the first cell are less than the allowed number of reported links in the first report, the UE may report at least a candidate link in the first report. The candidate link may be used to replace one of the failed links in the first cell. The UE may report (resource) index related to the candidate link in the first report, and/or a quality value related to the candidate link in the first report.

In one embodiment, the first set of resources may be transmitted in the first cell and/or the second cell. Alternatively, the first set of resources may be transmitted in the second cell, and not in the first cell. In addition, the first set of resources may be transmitted in a primary cell.

In one embodiment, the second set of resources may be transmitted in the first cell and/or in the second cell. In particular, the second set of resources may be transmitted in the second cell, and not in the first cell. The second set of resources may be transmitted in primary cell.

In one embodiment, the first cell may be a secondary cell, and the second cell may be a primary cell. The uplink resource for reporting may refer to frequency domain resource, time domain resource, code domain resource, or spatial domain resource.

In one embodiment, the UE may transmit the uplink resource or the physical uplink control channel in the second cell. The UE may monitor and/or receive PDCCH in the control resource set.

FIG. 19 is a flow chart 1900 according to one exemplary embodiment from the perspective of a UE. In step 1905, the UE is served and/or configured with a first cell and a second cell. In step 1910, the UE performs quality measurement derived from a set of resources in the second cell. In step 1915, the UE transmits a report for the first cell, wherein the report comprises the quality measurement result derived from part of a set of the resources in the second cell.

In one embodiment, the set of resources may comprise a set of CSI-RS resources or SS/PBCH blocks. The quality measurement result may mean RSRP or BLER derived by the UE.

In one embodiment, the report may comprise the quality measurement result related to quality of monitored control resource set in the first cell. The UE could monitor and/or receive PDCCH in the control resource set(s). The report may also comprise the quality measurement result related to the link quality in the first cell.

In one embodiment, the report may be per cell. The report may comprise an index related to the part of a set of the resources, and a quality value related to the part of a set of the resources. The report may be for beam reporting of the first cell. The report may be transmitted in the second cell.

In one embodiment, the report may be transmitted in the first cell. The first cell may be a secondary cell, and the second cell may be a primary cell.

In one embodiment, the UE may transmit the report in physical uplink control channel. The UE may be configured with resource configuration of the set of resource in the second cell.

In one embodiment, the set of resource in the second cell may be for beam measurement. In particular, the set of resource in the second cell may be for beam measurement of the second cell or the first cell. The quality measurement of the part of the set of resource in the second cell may refer to beam status of the first cell.

In one embodiment, the UE may transmit the report based on reporting configuration of the first cell. The reporting configuration may be linked to the resource configuration for L1-RSRP computation or beam measurement, or to resources indicated in the resource configuration for L1-RSRP computation or beam measurement. The reporting configuration may comprise at least time domain behavior of the report. The report may correspond to a measured quality or measurement result after receiving and/or measuring the resource(s) indicated in the resource configuration.

In one embodiment, the QCL assumption for receiving one of any downlink transmission in the first cell is referred to the resource configuration of the set of resource in the second cell. The antenna port(s) for receiving one of any downlink transmission in the first cell may be quasi co-located with one of any downlink resources transmitted in the second serving cell.

In one embodiment, the UE may use the same spatial TX parameters to transmit one of any uplink transmission in the second cell as that to transmit one of any uplink transmission in the first cell. The UE may be configured with a higher layer parameter for QCL indication in the second cell. The higher layer parameter may be associated with one of any downlink reference signal transmitted in the second cell where the higher layer parameter is configured.

In one embodiment, the UE may receive any downlink transmissions based on the higher layer parameter configured in the second cell. The UE may not be configured with the high layer parameter in the first serving cell.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a UE, wherein the UE is served and/or configured with a first cell and a second cell, the device 300 includes a program code 312 stored in the memory 310. The CPU 308 could execute program code 312 to enable the UE (i) to perform quality measurement derived from a set of resources in the second cell, and (ii) to transmit a report for the first cell, wherein the report comprises the quality measurement result derived from part of a set of the resources in the second cell. Furthermore, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.

FIG. 20 is a flow chart 2000 according to one exemplary embodiment from the perspective of a network. In step 2005, the network serves and/or configures a UE with a first cell and a second cell. In step 2010, the network receives from the UE a beam failure recovery request via a PRACH (Physical Random Access Channel) in the second cell, wherein the UE transmits the beam failure recovery request in response to the UE detecting that all links associated with monitored control resource set(s) in the second cell have failed. In step 2015, the network receives from the UE a first report via a PUCCH (Physical Uplink Control Channel) in the second cell, wherein the UE transmits the first report in response to the UE detecting that all links associated with monitored control resource set(s) in the first cell have failed.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a network, the device 300 includes a program code 312 stored in the memory 310. The CPU 308 could execute program code 312 to enable the UE (i) to serve and/or configures a UE with a first cell and a second cell, (ii) to receive from the UE a beam failure recovery request via a PRACH (Physical Random Access Channel) in the second cell, wherein the UE transmits the beam failure recovery request in response to the UE detecting that all links associated with monitored control resource set(s) in the second cell have failed, and (iii) to receive from the UE a first report via a PUCCH (Physical Uplink Control Channel) in the second cell, wherein the UE transmits the first report in response to the UE detecting that all links associated with monitored control resource set(s) in the first cell have failed. Furthermore, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.

In one embodiment, the network does not receive from the UE a request or a preamble on PRACH resource. In one embodiment, the UE transmits the request or the preamble in response to the UE detecting all links associated with monitored control resource set(s) in the first cell have failed.

In one embodiment, the first cell is a secondary cell and the second cell is a primary cell.

In one embodiment, the network receives a resource index related to a candidate link in the first report. In one embodiment, the resource index is a reference signal resource index, and the reference signal resource index comprises CSI-RS (Channel State Information Reference Signal) index and/or SSB (Synchronization Signal Block) index.

In one embodiment, the first report comprises at least an index related to the failed links and a quality value related to the failed links.

In one embodiment, the network keeps connecting with the UE via at least the second cell.

In one embodiment, the network receives a second report from the UE, wherein the second report is transmitted when at least one link associated with monitored control resource set in the first cell has not failed, and the second report is for normal beam reporting for reporting measured quality of downlink reference signals.

In one embodiment, the network receives the second report from the UE, wherein the second report is not transmitted when all links associated with monitored control resource set(s) in the first cell has failed.

In one embodiment, the first report and the second report have the same format structure, and the format structure is related to one or more of the followings: a bit width or length of the index, a bit width or length of the quality value, or a number of reported links.

In one embodiment, a link fails when quality of the connection between the UE and the network falls below a threshold, and the quality of the connection is RSRP (Radio Resource Control) or BLER (Block Error Rate) derived by the UE.

In one embodiment, the network transmits to the UE downlink transmission in the first cell and downlink reference signal resources in the second cell, wherein the antenna port for receiving transmitted downlink transmission is QCLed (Quasi Co-Located) with that for receiving transmitted downlink reference signal resources.

In one embodiment, the first cell and the second cell may be secondary cells. Alternatively, the first cell may be a secondary cell, and the second cell may be a primary cell.

In one embodiment, the index may mean a transmission configuration indication (TCI). An association between TCI state and resource for quality measurement may be configured and/or indicated by a higher layer.

In the context of the embodiments shown in FIGS. 17-20 and discussed above, in one embodiment, the second cell may be a reference cell of the first cell. The antenna port for receive downlink transmission in the first cell may be QCLed with downlink reference signal (resource) transmitted in the second cell.

Various aspects of the disclosure have been described above. It should be apparent that the teachings herein may be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative. Based on the teachings herein one skilled in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. As an example of some of the above concepts, in some aspects concurrent channels may be established based on pulse repetition frequencies. In some aspects concurrent channels may be established based on pulse position or offsets. In some aspects concurrent channels may be established based on time hopping sequences. In some aspects concurrent channels may be established based on pulse repetition frequencies, pulse positions or offsets, and time hopping sequences.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, processors, means, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two, which may be designed using source coding or some other technique), various forms of program or design code incorporating instructions (which may be referred to herein, for convenience, as “software” or a “software module”), or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

In addition, the various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented within or performed by an integrated circuit (“IC”), an access terminal, or an access point. The IC may comprise a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, electrical components, optical components, mechanical components, or any combination thereof designed to perform the functions described herein, and may execute codes or instructions that reside within the IC, outside of the IC, or both. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

It is understood that any specific order or hierarchy of steps in any disclosed process is an example of a sample approach. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged while remaining within the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

The steps of a method or algorithm described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module (e.g., including executable instructions and related data) and other data may reside in a data memory such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of computer-readable storage medium known in the art. A sample storage medium may be coupled to a machine such as, for example, a computer/processor (which may be referred to herein, for convenience, as a “processor”) such the processor can read information (e.g., code) from and write information to the storage medium. A sample storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in user equipment. In the alternative, the processor and the storage medium may reside as discrete components in user equipment. Moreover, in some aspects any suitable computer-program product may comprise a computer-readable medium comprising codes relating to one or more of the aspects of the disclosure. In some aspects a computer program product may comprise packaging materials.

While the invention has been described in connection with various aspects, it will be understood that the invention is capable of further modifications. This application is intended to cover any variations, uses or adaptation of the invention following, in general, the principles of the invention, and including such departures from the present disclosure as come within the known and customary practice within the art to which the invention pertains. 

What is claimed is:
 1. A method for a User Equipment (UE), comprising: the UE is configured with a first cell and a second cell by a network; the UE transmits a beam failure recovery request via a Physical Random Access Channel (PRACH) in the second cell; and the UE transmits a first report via a Physical Uplink Control Channel (PUCCH) in the second cell in response to the UE detecting that all links associated with at least one monitored control resource set in the first cell has failed.
 2. The method of claim 1, wherein the UE does not transmit a request or a preamble on PRACH resource in response to the UE detecting all links associated with the at least one monitored control resource set in the first cell has failed.
 3. The method of claim 1, wherein the first cell is a secondary cell and the second cell is a primary cell.
 4. The method of claim 1, wherein the first report comprises a reference signal resource index, and the reference signal resource index comprises Channel State Information Reference Signal (CSI-RS) index and/or Synchronization Signal Block (SSB) index.
 5. The method of claim 1, wherein the first report comprises at least an index related to failed links and a quality value related to failed links.
 6. The method of claim 1, wherein the first report includes a beam failure report transmitted via the PUCCH.
 7. The method of claim 1, wherein the PUCCH is used for a beam failure recovery request transmission.
 8. The method of claim 1, wherein the UE continues connecting with the network via at least the second cell.
 9. The method of claim 1, wherein the UE transmits a second report when at least one link associated with the at least one monitored control resource set in the first cell has not failed, and the second report is for normal beam reporting for reporting measured quality of downlink reference signals.
 10. The method of claim 9, wherein the UE does not transmit the second report when all links associated with at least one monitored control resource set in the first cell has failed.
 11. The method of claim 9, wherein the first report and the second report have the same format structure, and the format structure is related to one or more of the following: a bit width or length of an index, a bit width or length of a quality value, or a number of reported links.
 12. The method of claim 1, wherein a link is a connection between the UE and the network, and the link fails when the quality of the connection, which is Radio Resource Control (RSRP) or Block Error Rate (BLER) derived by the UE, falls below a threshold.
 13. The method of claim 1, wherein an antenna port for receiving downlink transmission in the first cell is Quasi Co-Located (QCLed) with that for receiving downlink reference signal resources transmitted in the second cell.
 14. A User Equipment (UE) wherein the UE is configured with a first cell and a second cell, comprising: a processor; and a memory operatively coupled to the processor, wherein the processor is configured to execute a program code to: transmit a beam failure recovery request via a Physical Random Access Channel (PRACH) in the second cell; and transmit a first report via a Physical Uplink Control Channel (PUCCH) in the second cell in response to the UE detecting that all links associated with at least one monitored control resource set in the first cell has failed.
 15. The UE of claim 14, wherein the UE does not transmit a request or a preamble on PRACH resource if all links associated with the at least one monitored control resource set in the first cell has failed.
 16. The UE of claim 14, wherein the first cell is a secondary cell and the second cell is a primary cell.
 17. The UE of claim 14, wherein the first report includes a beam failure report transmitted via the PUCCH, or wherein the PUCCH is used for beam failure recovery request transmission.
 18. The UE of claim 14, wherein the UE transmits a second report when at least one link associated with the at least one monitored control resource set in the first cell has not failed.
 19. The UE of claim 14, wherein a link is a connection between the UE and the network, and the link fails when the quality of the connection, which is Radio Resource Control (RSRP) or Block Error Rate (BLER) derived by the UE, falls below a threshold.
 20. The UE of claim 14, wherein an antenna port for receiving downlink transmission in the first cell is Quasi Co-Located (QCLed) with downlink reference signal resources transmitted in the second cell. 